The Planet at the End of the Universe
by Llywela
Summary: All together aboard the TARDIS once more, Sarah's feeling complacent about life as a time traveller, Harry's in denial, and the Doctor is only too glad of an excuse not to return to Earth when a distress call takes the trio to a remote planet at the far edge of the universe, where an isolated survey team has fallen prey to a mysterious malevolent force
1. Chapter 1

**Title**: The Planet at the End of the Universe  
**Show**: Classic Doctor Who  
**Characters**: Fourth Doctor, Sarah Jane Smith, Harry Sullivan  
**Rating**: PG  
**Summary**: All together aboard the TARDIS once more, Sarah's feeling complacent about life as a time traveller, Harry's in denial, and the Doctor is only too glad of an excuse not to return to Earth when a distress call takes the trio to a remote planet at the far edge of the universe, where an isolated survey team has fallen prey to a mysterious malevolent force.  
**Disclaimer**: Not so much alternate universe as universe alteration, this story is (very) loosely based on the season 13 serial _Planet of Evil_, written by Louis Marks – a re-imagining of what it might have been like if Harry had returned to the TARDIS instead of staying on Earth at the end of the previous adventure. All characters herein belong to the BBC, along with the original concept and anything else that seems familiar. I have borrowed them for this story and am making no profit from this.  
**Author's Note**: Although loosely based on _Planet of Evil_, this is not actually a re-telling of that story, partly because adding another companion alters both the dynamic and the flow of events, but mainly because although the Doctor and Sarah are as cute as all heck in _Planet of Evil_, I've never been overly fond of the story itself, so here I've simply taken the core concept and constructed a new plot on top of it.

**Part One**

"I think I must be mad," Harry Sullivan decided.

Leaning casually against a wall deep within the impossible labyrinth that was the Doctor's TARDIS, waiting for Sarah Jane Smith to re-emerge from the cavernous chamber the Doctor liked to call his wardrobe, it occurred to him that he'd thought that once before, back when the Doctor first invited him to step inside the rickety old police box he kept in the corner of his laboratory at UNIT HQ. He'd entered never suspecting for a moment what he might find, the door had closed behind him…and re-opened to reveal that the police box and its inhabitants were no longer at UNIT – no longer on Earth at all, for that matter, but on a space station thousands of years in the future. Madness had seemed a reasonable explanation, at the time, before the incredible reality of the situation had sunk in.

It was a different kind of madness entirely to have set foot inside the TARDIS again, this time knowing full well where it might lead.

"Who's mad?" Sarah's voice drifted out through the wardrobe door.

"I am."

The door opened just a crack to reveal her grinning face.

"Yes, probably," she teased, disappearing again. "Any particular reason why?"

"I'm here, aren't I?" he retorted, and felt a faint but distinct pang of regret. "Well, I mean, it was over, wasn't it? Both feet squarely planted on the green, green grass of home, after everything that's happened to us, all those adventures through time and space. And now here I am again. I must be mad."

It was absolutely not what he'd intended. Having never expected to leave Earth in the first place, when they finally found their way back he'd been only too glad to put all those adventures behind him and resume his post as UNIT's medical officer, deeply relieved to find that the position was still there, waiting for him. He'd had absolutely no intention of being lured back into the TARDIS again. No. Because he had a duty and a calling, responsibilities that he couldn't just walk away from on a whim.

Yet here he was again, and he still wasn't entirely sure how it had happened.

"You can always blame the Brig," Sarah's voice called from within the wardrobe. "If it makes you feel better."

"Well, he did tell me to see the Doctor safely back to London," Harry conceded. "And orders is orders."

"Well, there you are, then. Hey, what do you think?" Sarah emerged, dabbing briskly at her long dark hair with a brush, wearing a pair of pale blue jeans with a matching waistcoat over a kind of frilly blouse affair she'd unearthed from somewhere in the depths of the wardrobe.

Harry was no judge of female fashion, but the snug fit of the outfit was certainly something he could appreciate. He had an idea, though, that Sarah might not be terribly happy if he mentioned that, so he said, "Yes, very nice," instead, only for her to roll her eyes at him just as if he'd somehow still managed to say something dreadful.

"Anyway, it wasn't an _order_ order, was it?" she said, tossing the brush back through the wardrobe door before pulling it shut. "Not as such – you could have said no if you didn't want to come."

She fixed appraising eyes on him, eyes that seemed to wonder how anyone could say no to an invitation from the Doctor – and therein lay the rub, Harry realised, because he hadn't wanted to say no. As relieved as he'd been, after all those incredible adventures, to return to the normality and predictability of everyday life, to the duties and responsibilities he'd so unexpectedly left behind…when it had come right down to it, the moment of truth, he'd found that he wasn't quite ready for it to be over, to have to say goodbye.

And then the Brigadier had taken the decision out of his hands by telling him to go.

"My point stands," he said. "I must be mad."

Sarah grinned. "Gets into your blood, doesn't it? I'd have thought you'd be immune to it, though, sensible chap like you."

"At least I'm sailing under orders this time." And he wondered again which way he'd have jumped, if the choice had been left entirely to him.

"You keep telling yourself that, Harry!"

Sarah was chuckling, teasing; she was a journalist, a free spirit, answerable to no one but herself – how could she understand the difference it made, the importance of having official sanction to go off on a jaunt like this when there was no guarantee of ending up at the expected destination?

"I suppose we should get back and see what the Doctor's up to," she added. "Are you going to change first? You're bound to find something to suit. It's like an explosion in a costume factory in there."

"Yes, I've seen!" Harry remembered the parade of outrageous fancy dress the Doctor had put on for him when they first met only too well, and Sarah laughed again.

"There are normal clothes too, you know." She gestured at her own outfit by way of illustration.

"Oh, I know, I know." He glanced down at his uniform, almost tempted, before shaking his head. "Strictly speaking, I am still on duty, you know – and we are meant to be heading straight back to London."

It wasn't going to be as simple as that and he knew it – knew the Doctor more than well enough by now to know that he rarely ended up where he was supposed to be going and positively relished every detour, whether planned or unplanned – and Sarah's answering peal of laughter confirmed that suspicion.

"Yes, I'm sure that's what the Doctor intends," she said, leading the way back through the maze of corridors. "But I'm not so sure he's in any hurry to get there!"

They entered the console room to find the Doctor busily pottering away at the central controls, just where they'd left him. Sarah glanced at her watch, gave Harry a meaningful look and pointedly asked, "So how long have we been travelling now, would you say?"

The Doctor distractedly glanced up, eyes wide and shaggy curls standing on end, sticking out every which way. "Hmm? What's that, Sarah?"

She folded her arms across her chest in a strict schoolmistress pose as she accusingly, teasingly reminded him, "You promised we'd be back in London five minutes before leaving Loch Ness."

"Did I really say that?" It was quite remarkable that a centuries old alien could contrive to look so very innocent.

Sarah sighed and shook her head in mock dismay, bright brown eyes dancing with amusement. "You see, Harry, he's trying to wriggle out of it already."

"Like a worm on a hook," Harry agreed, taking his hat off and hanging it on the coat stand nearby, since it was clear they weren't going to be returning to duty at UNIT just yet.

He should probably be rather more concerned about that than he was, given how long they'd been AWOL last time, but it could hardly be considered a surprise. The Doctor's piloting skills were erratic at best and wilfully unpredictable at worst, and he'd known that, had walked back through those doors anyway and called it duty because the Brigadier had given the all-clear to go.

"Wriggle out of what?" The Doctor tossed the end of his outrageously long scarf back over his shoulder with an indignant flounce.

"Your promise," said Sarah.

He scowled, flicking at a switch. "Listen, we're on the edge of a space-time vortex here, and you're talking in minutes."

"Wriggle, wriggle, wriggle," she teased. "So what's gone wrong this time?"

"Nothing, nothing at all – what makes you think something's gone wrong?"

"Oh, because you always get rude when you're trying to cover up a mistake!"

"At least he can't blame me this time," Harry ruefully chipped in, remembering the torrent of abuse he'd received when his first trip in the TARDIS failed to land them where the Doctor had intended – and he'd barely even touched that helmic whatchamacallit.

"It's nothing of consequence," the Doctor airily dismissed. "Slight overshoot, that's all: easily rectified."

Sarah rolled her eyes at Harry and he could only shrug his agreement with that sentiment.

"So where are we, then?" he asked, deciding that it was high time they got down to the point of all this.

"We've come out of the time vortex at the wrong point, that's all," the Doctor defended, strolling around to the other side of the console to fiddle with the controls there. "A few years too late."

"How many years too late?" Sarah suspiciously asked, and Harry couldn't help thinking of the future Earth they'd visited, and their two trips to Nerva Space Station at two separate points in its history, thousands of years in the future. The Doctor's definition of 'a few years' tended not to bear a great deal of resemblance to his own.

The Doctor looked sheepish, and Harry knew he was right about that very broad definition of 'a few', even before the man admitted it was actually, "Thirty thousand," just as a shrill beeping sound began to ring out from somewhere on the central console.

"Saved by the bell, eh," Harry remarked, wondering what it meant, while Sarah simultaneously exclaimed, "That's a distress call!" and the Doctor was suddenly all business as he leant over his instruments.

"Someone's in trouble," he confirmed, his face lit up with excitement and anticipation – he was clearly only too glad of a good reason not to return to Earth just yet, and Harry wondered if he'd ever intended to do anything of the sort, valid excuse or no valid excuse.

"Where?" asked Sarah, who looked every bit as eager for a new adventure as the Doctor.

"Who knows?" The Doctor seemed delighted by the mystery. "Stand by for emergency materialisation."

dwdwdwdw

A thrill ran down Sarah's spine every time the TARDIS door opened to reveal a whole new world, even now, after she'd experienced so many adventures and so many strange new worlds.

She could smell this world long before she caught a glimpse of it, the rich, heady scents of moist, humid air and decaying vegetation wafting through the doors the moment they opened.

They'd landed in some kind of forest, she realised as she followed the Doctor out of the TARDIS, Harry at her heels. It was boggy underfoot and densely wooded, with fungi and vines hanging all around, their vivid red and purple hues offering immediate confirmation that, wherever this was, it wasn't anywhere on Earth.

It was murky, the tree cover too dense to allow much in the way of light to filter down to ground level, and a thick mist swirled around her ankles as she watched the Doctor pacing about a small clearing, his eyes glued to a device in his hand, some kind of radio-receiver that would home in on the precise location of the distress call that had brought them here. So the Doctor had claimed, anyway, but it seemed to be struggling already.

Sarah waited, then caught Harry's eye and shrugged; this was just typical of the Doctor.

Harry broke first. "Er…are we picking anything up there, Doctor?"

"Hmm?" was the Doctor's distracted reply, and they'd be here all day, at this rate, so Sarah quickly pressed the question home in the most pointed tone she could muster.

"Which way?"

The Doctor span on his heel in a 360 degree loop, smacking the side of the tracking device, peered at it again, and then pointed around and behind his own shoulder, spinning once more until he was facing in the direction his finger was pointing. "This way," he declared, setting off with long, confident strides.

Sarah caught Harry's eye again and he gave a rueful little grin. "Here we go again, eh."

She grinned back and tucked an arm through his to tug him along. "Come on, sailor."

It was tough going, picking their way through sticky mud underfoot and scrambling over fallen logs and under low-hanging branches and vines that seemed to glow faintly luminescent in the half-light of the jungle – and harder going still the way the Doctor kept stopping and starting and changing direction willy-nilly.

"You don't know where we are, do you?" Sarah teased after a while. If he did, he'd have told them by now – any excuse to show off.

He didn't take his eye off the device in his hand, his tone cheerful and airy. "Oh, with any luck, we're near enough to reach wherever it is –"

"That isn't what I meant," she interrupted, pushing a heavy branch aside to press past – and then realising too late that she'd let it swing back right into Harry's face. "Oops, sorry!"

"…before they're overwhelmed by whatever it was that made them trigger the alarm," the Doctor continued as if she hadn't spoken, over the top of Harry's reproachful 'ow, steady on, old thing'. "That is, if we're not too late already."

Once upon a time, Sarah might have pointed out that they'd landed within moments of receiving the distress call, so whatever was wrong here would have to be pretty bad to be too late already, but she'd long since learned that time travel didn't really work like that – a few moments for them in the TARDIS might have been hours, days or even weeks here on the planet – so she stuck to her point instead. "I mean, what planet is this?"

And now her boot was stuck in the mud, and true to form both men just wandered on ahead and left her to it.

"The signal's weak – fading fast," the Doctor's voice drifted back on the breeze, still following his own train of thought instead of answering her question. "But if we allow for the interference from the time warp…could you move any faster?"

Indignant, Sarah wrenched her boot free of the mud. "I'm doing the best I can!" she shouted after him, and as she spoke there was a sudden crackling sound somewhere nearby.

It was all the warning she had before she suddenly couldn't move any more – as if she'd been frozen to the spot, like an icicle. She could almost feel the blood solidifying in her veins, the breath freezing in her lungs, and there was something out there, she knew it, she could feel it, but she couldn't do anything to defend herself, not even cry out for help, could feel reality receding all around her, as if she was no longer inhabiting her own body but watching herself from afar, drifting further and further away by the second…

"Sarah?"

With a jolt, suddenly she was back, as if nothing had happened, she could breathe again, and Harry's face was about two inches from her own, worried blue eyes peering anxiously into hers, his hands loosely gripping her arms.

The Doctor was just behind him, looking curious. "All right there, Sarah? What's the matter?"

"I don't know," she croaked, mouth as dry as the Sahara all of a sudden. Moistening her lips with her tongue, she pushed Harry away and looked around, wondering what had just happened, and had to cough before she could speak again. "I thought…there was something here. Felt so odd, suddenly."

Harry scrubbed a hand through his neatly cropped curls as he looked around, his forehead creasing in a puzzled frown. "I didn't see anything."

"No, I didn't see it, I felt it," and she knew how that sounded, but it was the only way she could describe that sensation. "I couldn't move – as if my mind was being sucked right out of my body." The memory of it sent a shiver down her spine.

"But you're all right now?" The Doctor peered impassively down his long, beaky nose at her in that way he had that on the surface seemed so uncaring and detached but in fact simply meant that he was thinking very hard, trying to assemble whatever clues were available into some kind of pattern.

"Yes." And she laughed, both because she was so relieved that whatever it was had passed and because she was no longer certain she hadn't imagined it in the first place.

"Are you sure? You look a bit pale," said Harry, still hovering close by, solicitous and concerned, and that was all the incentive Sarah needed to pull herself together again, because she wasn't made of glass, whatever Harry might think.

"I'm fine. What's that you've found?" she asked to change the subject, and the Doctor glanced down at the object he was holding.

"Some kind of hand tool."

"We found it over there," Harry added, pointing, as Sarah took it from the Doctor's hand to get a better look: some kind of pick-axe, although very oddly shaped – slightly rusted, its handle worn smooth with use.

"So the people who sent that signal must be humanoid, then," she theorised, following as the Doctor set off again. "Well, they've got hands, at least – couldn't hold this with tentacles…"

She was still idly speculating as she pushed through a clump of hanging vines to step out into a large glade, in which a pre-fabricated dome-like structure with heavy steel doors seemed strangely incongruous. The Doctor had stopped short just ahead of her, staring, and Sarah followed the line of his eyes to see a horribly shrunken and dried up corpse that lay huddled in a defensive position nearby.

It had been too easy to forget, in the thrill of exploration, that they were here because someone had called for help. She felt a pang of regret, murmured, "Looks like we're too late."

"Several months too late, by the looks of him," the Doctor agreed, turning away as Harry pushed past and hurried over to examine the corpse.

Dead bodies held no appeal for Sarah, but learning more about where they were and what had happened here did, so she followed the Doctor over to a patch of cleared earth nearby that showed signs of recent disturbance. A number of hand-written signs were sticking out of the ground here and there to mark a series of impromptu graves, and she leaned in close to read one.

"Egard Lumb: died here 7y2 in the year 37,166."

She remembered the Doctor saying they'd come out of the time vortex thirty thousand years too late. The number hadn't seemed real somehow, until she saw it written down like this: a stark, sad memorial to a life lost tens of thousands of years after her own time – a life separated from her own by such an unimaginably vast span of time, and yet here she was.

"So is this a human settlement, do you think?" she asked, looking at the other grave markers, wondering what had happened to these people that they'd been too late to save them from.

The Doctor shrugged. "Human something, certainly."

"Well, I don't think that can be right," Harry's voice rang out. Sarah turned to see him sitting back on his heels alongside the corpse, wearing a thoughtful frown.

"What can't be right? He is human, isn't he?" The Doctor strode over to join him, looking slightly put out at the suggestion that he may be wrong, and Sarah followed, wrinkling her nose at the close-up view of the body, which was practically mummified.

"Oh yes, certainly," Harry agreed. "But…several months too late, you said. And it does look that way, at first glance, but this chap hasn't been dead all that long, in fact."

"Are you sure?" the Doctor demanded.

Harry nodded. "The desiccation gives it the appearance of age, of course, but all other indications are that the body is actually quite fresh," he said, sounding very certain and very professional. "Not more than 24 hours, I'd say – probably less."

"I'm not going to ask how you can tell. I don't think I want to know," Sarah said with a fastidious shudder. She didn't doubt that he could tell, though, and neither did the Doctor; however much he enjoyed mocking and teasing Harry for his old-fashioned manners and bumbling ways, the Doctor trusted his medical expertise implicitly – even if it was primitive, by Time Lord standards.

Harry flashed an amused grin at her as the Doctor turned away again, nodding thoughtfully. "So we have quite the mystery on our hands, it seems. Let's take a look inside."

dwdwdwdw

It was rather dark inside the curious structure they'd happened upon, so the first thing Harry did was stumble over something that had been left lying in the doorway.

"Mind your step," the Doctor promptly and belatedly cautioned, grinning that maddeningly impish grin of his as he stepped past, strode into the centre of the room and cheerfully boomed, "Anyone about?"

There was no reply.

The Doctor shrugged. "No one about."

While Sarah wondered if they couldn't have any lights and the Doctor went looking for the light switch, Harry bent to see what he'd tripped over, squinting at it in the dusky half-light: some piece of equipment or other, dropped there waiting for someone to come along and pick it up again. He wondered if there was anyone left who could – and what anyone might have been doing out here in the middle of nowhere to begin with.

Then he looked around, setting the object he'd tripped over down on a nearby workbench, and saw all the other equipment set up around and about the place.

"I say, what is this? Some kind of laboratory?" He poked at one or two of the pieces – cautiously, he'd learned that lesson the hard way – trying to guess at their function and wondering why anyone would set up a laboratory in the middle of nowhere like this. Some kind of exploration team, perhaps – it was far from his area of expertise.

"Or something," said the Doctor, fiddling with a control panel nearby, to no discernible effect. He frowned. "That's odd. Power's run down."

"Well, that would account for the weak signal," Sarah suggested, and the Doctor agreed.

"Ah," he cheerfully added. "Look here, an automatic distress button. May have been running for months, of course – but that chap out there died only recently, you say, Harry."

"Maybe as recently as last night," Harry confirmed. There was precious little he could ever be certain of, on these jaunts in the TARDIS, travelling through space and time to worlds he could never even have dreamed of, but he knew where he was with a human corpse and despite superficial appearances that one was definitely fresh.

The Doctor continued to explore, tracing power cables back from the computer console.

"Renewable energy source," he announced. "It's powered by a high capacity solar cell, highly efficient – strange that it should have run down, then. Not enough sunlight, perhaps – or it may be damaged." He seemed to be thoroughly enjoying the mystery of it all, well and truly in his element.

"We're still in the solar system, then," Sarah suggested.

"_A_ planetary system, certainly – but which star?" said the Doctor. "Wherever we are, we're a long way out."

Where they were was a valid question, of course, but as Harry peered out of the window at the dead man outside, who'd fallen so close to the graves of his comrades, a rather more pressing concern was on his mind.

"I wonder what happened here."

The Doctor made a thoughtful moue.

"Well, this is clearly the base for some kind of scientific expedition, wouldn't you say?" he said, and Harry nodded, feeling stupidly pleased to have reached the same conclusion himself. "A geological survey, if I'm any judge – and I am, you know. Something must have gone wrong, and they sent out a distress signal."

"And died before help arrived," Sarah added.

"Something like that – a lost expedition."

"Yes, but what was it that went wrong?" was what Harry wanted to know. "I mean, what could do that to a man?" He nodded toward the corpse outside.

"Good point – I think we'd better find out. There was no obvious cause of death, was there?"

"Not that I could see, but I hardly had time for a detailed examination. I can take another look."

"Good," the Doctor briskly agreed. "While you're doing that, I'll just pop back to the TARDIS and fetch my spectromixer, to fix our position by that star. Then I'll repair this power cell and try to make contact."

Make contact with whom, exactly? Before Harry could ask, Sarah had piped up, "Well, you can get on with that now. I'll fetch the spectromixer. I know where you keep it."

"Oh, I'm not sure you want to go wandering around out there all on your own, Sarah." The protest came automatically, instinctively, and Harry knew even as he said it that Sarah would be annoyed, but still. They didn't know what might have happened here and she'd been so certain earlier that there was something out there.

Sure enough, Sarah promptly retorted, "If I didn't want to go, Harry, I wouldn't have offered."

"Well, yes, but we don't know what might be out there," he reminded her. "_Something_ killed all these people."

"Oh, it seems quiet enough for now," was the Doctor's verdict, and that seemed to settle that, for better or for worse, and it wasn't all that far to go, after all. So, while Sarah assured the Doctor that she knew the way back to the TARDIS, Harry headed on out for another look at that corpse.

Sarah passed him a few moments later, the TARDIS key dangling from her hand. "See you in a bit, Harry," she called over her shoulder as she headed off through the jungle, fearless as always. Plenty of other girls, he imagined, might have thought twice before volunteering to wander around a strange, unknown world like this all alone, even without the mystery of what might have happened to this lost expedition, but not Sarah.

Rather wishing for better light to see by, Harry knelt to examine the corpse, noting again the strange synthetic material of the man's one-piece uniform and the complex design of the wrist-piece he was wearing, surely something far more high-tech than a mere watch. Despite the aged appearance of the corpse, both the outfit and the wrist-piece were pristine, the first of a number of clues to indicate that the body couldn't have been lying out here exposed to the elements for more than a few hours…but that was about as far as his examination got before he heard the Doctor calling him and hurried back inside.

The Doctor had gone through to the rear compartment of the base, he saw, some kind of bunkroom – and lying just inside the door was a second corpse, female, as pitiful and desiccated as the first.

"Another one!" Harry hurried over and dropped to his knees alongside the body.

"Yes." The Doctor was looking troubled now. "And Sarah's out there."

Harry didn't like to say 'I told you so', but the Doctor's concern wasn't exactly reassuring. He made a rapid examination, worried now. "Just like the chap outside. No obvious wounds, no sign of trauma – exsanguination, dehydration, nothing to indicate what might have caused it. Shouldn't we –?"

He broke off as a beam of light suddenly swept the room before coming to rest on him, kneeling there alongside the corpse. He looked up in surprise, hand rising to shade his eyes, and, out of the corner of his eye, saw the Doctor turn to see who was there.

There were three people stood in the doorway, dressed in uniforms of blue, flashlights in hand…and they were also carrying guns, aimed squarely at the Doctor and himself.

Captured at gunpoint was getting to be a familiar feeling. Harry sat back on his heels and raised his hands, reflecting that Sarah might have been well off after all, clearing off back to the TARDIS before this.

dwdwdwdw

Sarah couldn't shake the feeling that she was being watched as she approached the TARDIS. It was an uncomfortable feeling, coming at the end of a journey that had been a lot creepier alone than in company, the eerie whistle of the wind through the trees bringing her experience earlier back to the forefront of her mind. At the time she'd all but convinced herself she'd imagined it, but alone in the rapidly darkening woods, lit only by the strange phosphorescence of the fungi and vines, she could no longer be so sure, and now was certain she could feel eyes fixed upon her back.

A branch snapped, somewhere behind her, and she whirled around, expecting to see she had no idea what – but there was nothing there.

_You're imagining things, stop it_, she told herself as she put the key in the lock…and then something rustled, somewhere off in the bushes close by, and she froze, listening intently, because she definitely hadn't imagined that.

An animal, perhaps – but there hadn't been any trace of any such thing the whole time they'd been here, and that was strange in itself. You'd expect a forest like this to be teeming with wildlife, surely. What kind of world was this?

And if it wasn't an animal moving around in that bush…what was it?

"Hello? Is someone there?" she called out, tucking the key back into a pocket as she peered cautiously into the undergrowth, straining to make out shapes in the gloom. Was something there? Or had she imagined it after all?

Another rustle – and something large came lurching out of the bushes.

Sarah jumped back with a gasp of alarm, relaxing only slightly as she realised it was neither an animal nor a monster but a man, a human man: wild-eyed and dishevelled and dressed in the same kind of uniform as that corpse back at the base, staring at her as if he'd seen a ghost.

"Who are you?" His voice was the merest whisper, hoarse and disbelieving. A grimy hand rose to clutch at the greasy thatch of mouse-coloured hair that covered his head, eyes wide with disbelief. "Where've you come from? There's no one here – no one left; only me. Can't be here, you can't be here. What are you? Why're you here?"

A survivor, Sarah realised. He was a survivor of whatever had happened to the survey team – and half-mad with shock, by the looks of it.

"It's all right, don't be afraid," she quickly called out in what she hoped was a soothing tone. "My name is Sarah. Sarah Jane Smith. I'm here to help."

"Help?" He eyeballed her warily.

"Yes, we picked up your distress signal, we came to help." She watched him closely, maintaining a safe distance, since he seemed unstable, to say the least…but if he'd seen his entire team die, buried most of them, perhaps that was hardly surprising.

She waited as a myriad of conflicting emotions flitted across the man's face, unnerved by the strange, mad light in his eyes. Did he even understand what she was saying, half-crazed as he was? What must he have been through, to reduce him to this?

"What's your name?" she tried asking.

A branch snapped, somewhere off in the distance, and they both jumped, startled by the sudden sound.

"Something coming," the man muttered to himself in sharp, staccato tones. "Someone coming – where're they from, why're they here – how're they here? Too many people…"

"It's probably my friends, come looking for me," Sarah gently offered, and he whirled around as if he'd forgotten she was there, darted forward and grabbed her wrist, started tugging her toward the bushes. She pulled away in alarm. "Hey, let go, what do you think you're doing?"

"Hide!" The warning was hissed, fierce, and he caught at her arm again, frantic. "I don't know who's there, what they want, are they safe – who to trust, what to do! We must hide! Watch and see."

He was so agitated that she allowed him to pull her into the bushes, ducking down out of sight just in time to avoid being seen by two young men in uniform, one very dark and the other very fair, strolling through the jungle so intent on their conversation they didn't spot the TARDIS until they were almost on top of it. Crouching low, Sarah watched as they regarded it with deep consternation, reporting their find to someone else via tiny handheld radio-communicators.

"Why are we hiding? Aren't they with you?" she whispered to her strange companion, confused because the newcomers were wearing the same kind of uniform as his – a different colour, blue instead of brown, but the design was the same and she might have assumed they were more survivors of the ill-fated survey team if this one hadn't been at such pains to hide from them.

He shook his head, watching the other men intently, wide-eyed and twitching. "No, no," he muttered, pulling fretfully at his stubbled jaw. "Where are they from, why are they here? You shouldn't be here, no one should be here."

He turned on her so suddenly, so fiercely, it was all she could do not to startle away from him and give their hiding place away.

"Shh, it's all right, it's all right," she soothed, torn between the conflicting need to both focus on the madman at her side and keep a sharp eye on those other men, because they were attaching something to the sides of the TARDIS – what were they doing?

They stepped back, spoke into their communicators again, fiddled with a device they were carrying…and the TARDIS disappeared.

Sarah gaped in shock.


	2. Chapter 2

**Part Two**

"You were 'just passing'? Is that what you expect me to believe?" demanded the man who'd introduced himself as Commander Armin Vishinsky, second-in-command of the space probe KX9-06 and leader of an investigatory landing party; an older man, sallow and grizzled with worry lines worn deep around shrewd eyes, wearing a severe expression and brandishing a gun.

"Er." Harry looked to the Doctor, to see if he might step in to field the questions now – talking his way out of trouble was generally his forte, after all – but the man showed no sign whatsoever of joining the conversation, his earlier good humour evaporated into pensive silence, leaning casually against a worktop with his hands stuffed deep in his pockets, wide blue eyes fixed on nothing in particular, lost in his own thoughts.

He wasn't going to be any help. Harry turned back to Vishinsky and tried again.

"Well, it's still true, whether you believe us or not," he insisted, wondering how he could convince the man. "We were just passing – well, sort of – when we picked up some kind of distress call, thought we'd better pop down and investigate, see if there was anything we could do." He looked from one unconvinced face to another, and added, "Look, you must have heard it yourselves. Isn't that why you're here?"

"Distress call," Vishinsky disbelievingly repeated. "There was no distress call – any signal would have been monitored by our receivers."

"Perhaps my receivers are better than yours," the Doctor spoke up at last with a languid smile. One of the guards snapped at him to be quiet, and he reproachfully added, "My manners certainly are," with an expressive eye-roll in Harry's direction.

"Zeta Minor is in the farthest reaches of space, beyond Cygnus A," Vishinsky crisply declared, still looking stern but also rather tired and worried, and Harry was suddenly reminded of a headmaster he'd had at prep school, a kindly man who'd never wanted to have to play the disciplinarian but nonetheless came down like a tonne of bricks when he had to, strict but fair. "It's as distant again from Ortoro galaxy as that galaxy is from the Anterades, the very end of the known universe. No one 'just passes by' this region. Yet here you are. So let me ask you again: what are you doing here, and what have you done to Professor Sorenson's survey team?"

"That's a very good question, Commander Vishinsky," said the Doctor – rather too cheerfully, Harry felt, in the circumstances. "What happened to the survey team? I think it's high time we began to find out, don't you?"

"If you would explain yourselves properly, perhaps we might," Vishinsky snapped, adding in a curt aside to one of his adjutants, "Find out what's wrong with the lights in here, Landa. This would be easier if we could see clearly."

"I believe you'll find the fault in the main solar cell," the Doctor helpfully suggested as the petite, pretty female operative moved to examine the control console, holstering her weapon. "I had intended to repair it, but I'm afraid we've been rather waylaid, haven't we, Harry?"

"We certainly have, Doctor," Harry had to agree, folding his arms across his chest.

"Then why damage the cell in the first place?" Vishinsky had what were popularly known as beetling brows, startlingly white, and they all but met in the middle as he frowned.

"There you go again," said the Doctor with a smile and a shrug. "You're assuming that my colleague and I are responsible for what's happened here, when in fact that couldn't be further from the truth. We came to investigate –"

"This phantom distress signal, yes, so you say," Vishinsky interrupted.

"It's still true," Harry told him, although in all honesty he could see how it looked – if the situation were reversed and UNIT found a pair of possibly alien strangers standing over a pile of corpses, they'd be inclined to suspicion, as well.

"Yet I can't possibly believe it." Vishinsky looked exasperated. "The last report received by Morestran Federal Council indicated that Professor Sorenson and his team had made a breakthrough in their research, a discovery of crucial importance – and then all contact with them was lost. Our space probe was diverted to investigate, and what do we find? The pair of you standing over their graves, on a planet you could only have reached by design. Yet you claim innocence? Espionage, more like: industrial espionage and a cold-blooded attempt at stealing Professor Sorenson's findings. Give me one good reason why I shouldn't simply charge you with eight counts of murder and have done with it."

The Doctor's ears pricked up. "_Eight_ counts of murder? You mean to say there were eight members of the survey team? That's very interesting – isn't that very interesting, Harry?"

"Interesting? You call murder 'interesting'?" Vishinsky spluttered in fury.

Harry, though, saw at once what the Doctor was getting at. "Five graves, two corpses – you're a man short, Commander."

dwdwdwdw

"It wasn't my fault," Sarah's strange new acquaintance muttered as he pushed and shoved his way through the boggy undergrowth. Sarah had no idea where he was leading her but had to trot to keep pace with him, ducking beneath low-hanging branches wound round with vines that glowed faintly luminescent in the dark, and stumbling over roots and through thick mud; these lovely boots she'd found in the Doctor's wardrobe would never be the same again. "It wasn't my fault. I had to keep working, my researches are vital – mustn't stop, can't give up. It wasn't my fault."

"I'm sure it wasn't," Sarah attempted to reassure him, telling herself to tread carefully because the man was unstable and unpredictable. Torn between sympathy for his pitiful condition and concern for where his mental state might lead, she half-wished she'd gone after those other men, to find out what they'd done with the TARDIS, but they'd moved off almost immediately leaving this one her best chance of finding out what was going on here – if she could only manage to get some sense out of him. "Perhaps if you told me where we're going…"

"My samples!" he exclaimed, as if he'd assumed it were obvious. "My equipment, my work. Who are these strangers? Stealing my work!"

"They probably came because of the distress signal," Sarah suggested in the most soothing tone she could muster. "Like we did."

He stopped short and swung around sharply, fixed her with eyes that were suddenly shrewd and suspicious. "What distress signal? I set no distress signal."

"Well someone did," Sarah told him. "Because I heard it, and those other people must have heard it as well, mustn't they, or why else would they be here?"

There was a note of hysteria in his answering laugh. "Do you have any idea where you are?"

He didn't wait for an answer, charging off again even faster than before.

Sarah began to follow but stopped almost at once because she could hear that crackling sound once more, the humid air turning to frost in her lungs before she had even a second to react – it was happening again, she was trapped, unable to move, unable to breathe – why had she dismissed this, how could she ever have persuaded herself she'd imagined it…?

It lasted only a second this time and then again was gone as abruptly as it had come, leaving her gasping and shivering. That wild-eyed man, heavy-set yet haggard, had come back, stood staring at her as if he'd never seen her before.

"Full night," he muttered. "Full night, they come at night. Can't trust what you see." He narrowed his eyes to glare at her. "Are you real?"

dwdwdwdw

"Blue box successfully transposed to probe for investigation," said a tinny voice over Vishinsky's communication device. "We'll continue the search."

Harry watched as Vishinsky, looking harassed, closed down the communicator and moved to chivvy the female crewmember, Landa, as she worked on the connections to the power cell, or some such. The other crewman – a swarthy, long-legged chap with a shock of improbably-coloured hair that couldn't possibly be regulation – was taking the opportunity to slouch at the door rather than guard it, since his commander's eyes weren't on him. Harry and the Doctor, shoved into a quiet corner for safekeeping, seemed to have been forgotten for the moment.

He tried sidling a little closer to the Doctor, who didn't appear to be paying the blindest bit of attention, standing with his hands in his pockets and his eyes blankly fixed on the wall opposite, again staring at nothing in a manner that was almost unnerving.

"They've got the TARDIS," Harry murmured under his breath, wondering if Sarah had made it there before it was found or if she was still out wandering the woods someplace trying to avoid the rest of the search team – probably best not to mention her within earshot of Vishinsky's chaps, just in case.

"Oh, you noticed that, too." Roused from his semi-trance, the Doctor shook his head sadly. "Do you know, Harry, this trip isn't turning out at all how I'd envisaged."

"Isn't it?" Mysterious corpses, guns, captivity – it all seemed rather par for the course to Harry, and he said so. "It's more or less exactly what I was expecting."

"And still you came." The Doctor seemed amused. "We'll make an adventurer of you yet, Harry."

"Just following orders, Doctor," he was quick to point out, since it had been the Brigadier's instruction to see the Doctor safely back to London that brought him back aboard for this trip, after all, but the Doctor only chuckled in much the same way Sarah had earlier.

"If you insist, Harry – hang about, what are they doing now?"

Vishinsky was on the communicator again, this time to his commanding officer up on the orbiting space probe.

"The landing site is moving to obverse, so we'll come in now, we'll miss the window if we wait for dawn," the captain's voice announced over the receiver. "I'll see to the prisoners myself when we arrive. Salamar out."

Tucking the communicator away, Vishinsky swung around with a brusque, "As you were, Wijaya," to the guard at the door, who snapped to attention with a little grin that was pure chagrin at being caught lounging on duty, not that Vishinsky waited to see this reaction, continuing his arc around to Harry and the Doctor. "A full and immediate confession would save you great discomfort," he warned, rather worryingly. Harry shot an uneasy glance toward the Doctor, who seemed remarkably untroubled by the threat.

"Discomfort? You mean you're going to torture us," he said, far more calmly than the situation warranted, Harry felt, visions of that torture device the Kaleds had strapped him into back on Skaro flashing through his mind. It had been switched on only for a matter of seconds, in the end, but they were seconds he was not anxious to relive.

"_Interrogate_ you," Vishinsky corrected, and that might have been reassuring if he hadn't added, "And nobody, I'm afraid, withstands Morestran interrogation for very long."

"We've already told you everything we know," Harry burst out. "You can ask as many questions as you like; the story isn't going to change."

The Doctor made a shushing sound and patted his hand in a manner he probably intended to be soothing, eyes fixed on Vishinsky, stern and searching. "It's all right, Harry. Commander Vishinsky is a reasonable man, I'm sure he'll –"

"Sir," Landa interrupted.

Vishinsky swung around, irritated. "Yes, what now?"

Landa was no taller than Sarah, sleek black hair neatly cropped to a chin-length bob and uniform immaculate. Her tawny-brown skin flushed to pink around the cheeks in the face of her commander's ill temper, but she stood her ground, back straight and bearing upright. "I thought you'd want to know, sir. I've checked all the connections to be certain – the distress beacon _is_ active, sir."

Vishinsky was visibly thrown. "It can't be. We'd have picked up the signal."

"That's the thing, sir – there is no signal, at least not strong enough for the probe to receive. It's extremely weak, highly localised – wouldn't extend far beyond these walls, in fact."

"Which takes us back to the faulty solar cell," said the Doctor, beaming at the girl with delight. "No reserve, so when the beacon was activated it must have redirected what little power was available from other systems until that too was depleted – before your ship came within range. My own receivers are far more acute, of course. Well done…I'm sorry, I didn't catch your name."

She hesitated, darting uncertain side eyes toward Vishinsky before answering. "Technician Landa, Samina Landa, sir."

"Oh, I'm not a sir and there's no really need to stand on ceremony, Technician Samina Landa," said the Doctor. "It's a pleasure to meet you – now, about that solar cell –"

"Enough," thundered Vishinsky. He looked confused, and didn't seem the sort of man who much appreciated being confused. "I don't know exactly what happened here, but I do know this: seven Morestran field researchers have been killed, the eighth is missing, and you two are the only suspects we have. Now, Captain Salamar is bringing the probe down to the planet, you will be interrogated and we will get to the bottom of the matter, one way or another."

"Or," said the Doctor, "We could all work together to solve the mystery – my colleague and I really could help you, if you'd only let us."

"You're suspects in a murder investigation," said Vishinsky with deep exasperation. "How can we trust anything you say?"

Harry had been thinking about that. "Wouldn't the survey team have kept some kind of log?" he suggested, inspired as much by vague memories of _Star Trek_ as by his own practical experience of lab-based research, and every eye in the room was suddenly upon him. "Well, whatever happened, if they had time to conduct burials, they'll also have kept records of some kind, surely."

Vishinsky didn't seem entirely convinced but the Doctor nodded approvingly. "Good thinking, Harry. So what do you say, Commander? Must we sit around counting one another's eyebrow hairs waiting for Captain Salamar to arrive? Or shall we see what we can do about restoring power and get on with the investigation while we wait? Because I can assure you that my friend and I had nothing to do with the deaths of these people – but something did, and it's still out there."

dwdwdwdw

Tired, thirsty and footsore, Sarah deeply regretted allowing herself to be led so far off the beaten track, but there was no turning back now, not if she wanted to learn anything about whatever was going on here – which she did.

"Here. Here, you see? It's my work, my researches – it's important. I had to stay, it's important," gabbled her odd, traumatised companion, guiding her up a steep rocky incline and through a narrow cleft onto a kind of plateau.

It was chilly up here on the hillside, and away from the luminescence of the vines that proliferated throughout the jungle, with only the pale light of the stars to see by, it was hard to make out much detail, only shadows and darker shadows and odd little glints and twinkles here and there, their source unknown. The man, though, didn't seem to mind the dark at all, lunging away into the shadows as surefooted as a mountain goat, leaving Sarah to fumble blindly at the rocks for some kind of guide.

She couldn't see how big this plateau either was or wasn't. She couldn't see where the man had gone. She couldn't even see the gap in the rocks they'd come through to get here, which meant she'd struggle to find her way back down to the jungle in search of the Doctor and Harry, to warn them about the disappearance of the TARDIS and the presence of these other people. She could have kicked herself – coming all this way and for what?

A light came on, startlingly bright, dazzling her. Blinking rapidly to clear dancing afterimages from her eyes, she slowly made out the figure of her strange new companion fussing over a jumble of scientific equipment as a mother might her lost child. He'd switched on a lamp, reached now to light another, and she was grateful for the illumination this offered, allowing her to make out her surroundings. High enough and rocky enough to be free of the marsh and mud of the jungle, the plateau was dominated by a large pool within a gaping crater, around which lay clusters of gemstones – hundreds, maybe thousands of them, littering the ground.

Sarah stared in wonder, knelt to take up a handful of the shimmering gems and marvelled at the quantity and beauty of them, their shifting colours, iridescent in the lamplight, like nothing she'd ever seen before. They were cold to the touch, heavier than they looked, and gave off a curious tingling sensation – a bit like the static electricity you got from rubbing a balloon against your hair. What on Earth – or, rather, what _not_ on Earth were they?

A hand clamped around her wrist, forcing her to drop the jewels. She looked up into the bloodshot hazel eyes of her strange companion.

"No," he said, suddenly fierce. "No touching – they're not to touch."

"I'm sorry." Pulling her wrist free, Sarah held her hands up to show that they were now empty, not wanting to antagonise him needlessly. He seemed to have accepted her as a friend, but he was unpredictable and she did not want him to turn on her. "I won't touch if you don't want me to."

He was satisfied and turned back to his equipment with a nod. Sarah watched him for a moment, wondering what he was doing – the Doctor would know – and, more to the point, wondering what she should do next. Could she learn anything from this madman, or do anything for him? Or should she try to find her way back to Harry and the Doctor now? They'd be worried about her. She was worried about them, with the TARDIS captured.

The man was rooting through his equipment and some of it spilled, scattering across the rocky floor. She bent to help him gather it together again and picked up a notebook, which had a neat little label in the corner.

"Evan Danziger," she read. The name seemed familiar, somehow, but she couldn't quite place it. "Is that you? Are you Evan Danziger?"

He startled upon hearing the name and snatched the book from her hand, stared at its label in sudden distress, nostrils flaring and lips trembling.

"No." Head shaking, his voice was no more than a whisper now, his eyes wide, almost frightened, like a lost little boy. "No, I was professor….professor – this was my team. My team…."

Evan Danziger – it was one of the names inscribed on the grave markers back at the base, Sarah suddenly remembered. "What happened to your team, Professor?"

He stared at her, eyes bright and brimming. "It wasn't my fault."

"I'm sure that's true," she offered, knowing the reassurance was meaningless, hoping it would soothe him into saying something even remotely informative anyway.

"My work is important," he insisted. "It had to continue."

Curiosity well and truly piqued, Sarah tried a different tack. "Can you tell me about your work? Why was it so important?"

His gaze shifted to take in the plateau, the gemstones, that jumble of scientific equipment. There was a dazed look about him now, yet he also seemed more lucid than she'd seen him yet. Would he explain what had happened here?

As he opened his mouth to speak, there was a shout from out in the jungle – a male voice, a cry of pure anguish.

Was that Harry? Or the Doctor?

The professor and whatever he was about to say flew out of Sarah's mind entirely. She snatched up one of the lamps and ran, scrambling back through the cleft and down the rocky incline to the jungle, in search of the owner of that voice.

dwdwdwdw

"So we are going to just sit around counting one another's eyebrow hairs until Captain Salamar arrives, then," Harry grumbled, pacing around the bunk room in exasperation, Commander Vishinsky having conceded that restoring power and attempting to access the survey team's logs would be a good step forward in the investigation, while remaining unwilling to allow murder suspects to play any part in that work. He'd had the two of them locked away in here, with that corpse for company, while he and his team got on with repairs.

The Doctor was no help – he'd just sat himself down on a bunk and drifted back off into that semi-trance of his once more, the moment they were shoved in here.

"Shh," he said, not even glancing in Harry's direction. "I'm thinking."

Harry sighed and paced some more, wondering how they could possibly convince these people they were telling the truth and what Sarah might have been up to all this time, if she was safe. He looked out of the window to see if there was any sign of the probe yet, and then froze because he thought he'd heard something.

"I say, did you hear that?"

There was only silence now, both without and within the room. He was sure though.

"Doctor, I heard something."

The Doctor roused slightly. "What kind of something?"

"A shout – Sarah's still out there, you know."

That got his interest. "Was it Sarah who shouted?"

"Well, I don't think so," Harry had to admit, half-expecting to be given a lecture about raising false alarms, but the Doctor only frowned.

"I was hoping for a quick word with Captain Salamar – still, if you're sure…" He bounced to his feet, suddenly all business. "We'd better investigate, hadn't we?"

He made it sound so easy. "Er, Doctor – aren't you forgetting something?"

The Doctor's eyes went wide and round – well, wider and rounder, that was. "Am I?"

Harry gestured at the door. "We're locked in."

The Doctor grinned. "No, Harry, I think you're forgetting something – and so is Commander Vishinsky. Power locks…but there's no power to power the locks. So it doesn't lock."

He reached for the door – but he _had_ forgotten something, Harry realised. "Wait, we can't go out there. That's where Vishinsky is."

The Doctor stopped, hand already on the door, and looked slightly embarrassed. "Ah," he said. "Yes. Good point."

"Er…the window?" Harry offered, reasoning that if there was no power to seal the door locks, then surely the same would also be true of the only other possible exit from the room.

"I knew I'd brought you along for a reason, Harry." The Doctor's grin was pure mischief and Harry got the distinct impression he was being sent up. "Let's go."

dwdwdwdw

Struggling through a particularly boggy bit of ground that threatened to tug her boots from her feet, Sarah wasn't entirely sure she was going the right way. That shout had come from this direction, hadn't it? She could no longer tell.

She hauled her way to marginally drier, firmer land, fought her way free of a prickly vine that caught at her clothes and snarled in her hair, and stumbled out into a small clearing where a uniformed figure was huddled over a body, hands fluttering as if unsure what to do.

She'd come the right way after all, then.

"Hello?" She approached cautiously and crouched to look at the corpse, which was just like the one back at the base – dried up like a thousand-year-old mummy – and then looked up into a narrow, high-cheek-boned face with the blackest skin she'd ever seen, currently blanched with shock. He was very young and very afraid, so shaken that he didn't even question her presence.

It was the two men she'd seen earlier, she was sure of it – the ones who'd made the TARDIS disappear. Looking down at the corpse again, she remembered noticing what a contrast they made, the one so dark and the other so fair. She'd seen the dead man no more than an hour ago, surely, as hale and healthy as they came…how could he have been reduced to a mere husk like this, and so fast? His bright blond hair was shrivelled up like old straw, milk-fair skin turned waxen and grey, once rosy cheeks now sunken and hollow…Harry had said the other corpse was fresh, but she wasn't sure she'd truly believed it until this moment. What could do this to a man?

"H-he's dead," stammered the young man. "It's Bartrum. He's dead."

"I know," Sarah soothed. "I know. Can you tell me what happened?"

"I just stopped for a minute – only a minute. My boot was loose – stuck in the mud. I thought he'd wait. He didn't wait…" He clasped his hands behind his bowed head and brought his elbows together to hide his face, palms pressed flat against the multiple tiny braids that ran tight against his scalp, ending in so many inch-long pigtails.

Touched by his distress, Sarah reached out to rest a hand on his shoulder. "It's all right. It's not your fault. What's your name?"

"Ola," he muttered, and then blinked, dashed a hand across his eyes and made an attempt to pull himself together. "Oh, um, that is – Sub-ensign Utoblo. Ola Utoblo. I was…I should…I need to call this in…I have to…" He stopped, frowned as if seeing her for the first time. "Wait – who are you?"

"Sarah Jane Smith. We heard a distress signal and stopped to see if we could help. Isn't that why you're here, as well?"

He shook his head slowly, suspicion creeping into his eyes. "You're with the others – Commander Vishinsky says you're responsible. You did this – you killed him."

"No!" Sarah protested in alarm, startled both by the accusation and the implication. 'The others', he'd said. Where were the Doctor and Harry? What had happened to them? "Think about it, Ola – how could I have killed him? I wasn't here."

"I don't know that – I didn't see what happened. You could have killed him and then come back…" A note of alarm tinged his voice now. He jerked away and pushed upright, reaching for the gun holstered on his belt. "You won't do that to me, not to me. Stand up and start moving. I'm taking you back to base. The captain will know what to do with you."

dwdwdwdw

"Which way?" asked the Doctor, scrambling out of the bunkroom window so hot on Harry's heels he almost landed on top of him.

Hopping hurriedly out of the way, Harry hesitated, because he had absolutely no idea which direction the very distant shout he'd heard might or might not have come from. "Er…"

He got no further as a faint whine he'd been only vaguely aware of for the last few minutes became ear-splitting, the whole glade suddenly lit up from above, and the Doctor caught at his arm to stop him going any further. "Look out!"

It was the probe – a massive spheroid, landing struts extended – making its final, impressively vertical descent directly in their path, the scorching heat of its engines forcing them to stumble back and away. There was a time the sight of an honest-to-goodness spaceship would have inspired awe, but all Harry could think just now was that it was cutting off the route back to the TARDIS, the way Sarah would have gone.

A moment later there was another shout, this one much closer at hand: Commander Vishinky and his aides had come out of the base and spotted them. So much for making a clean getaway.

The Doctor glanced back and then quickly turned away again, as if he thought they might not see him if he couldn't see them. "Don't look now, Harry," he muttered, slinging an arm around Harry's shoulders, "But I think the good commander might be onto us."

"Stay where you are!" shouted Vishinsky.

Harry glanced over his shoulder to see that all three were brandishing their weapons – had the Doctor had ever, he wondered, landed in a place without anything like this happening? "I think you might be right, Doctor."

They exchanged rueful glances and raised their hands, turning around in unison to face their captors.

"Come back here," Vishinsky ordered.

"Doctor – Harry!" The sudden shout startled them all.

It was Sarah, emerging from the forest around the side of the probe as it settled onto the ground, that ear-splitting whine finally beginning to subside – and she was at gunpoint, another of Vishinsky's men at her back.

"Utoblo, what is this? Where's Bartrum?" Vishinsky called out.

"He's dead, she did something to him and he's dead!"

"I didn't!" Sarah indignantly protested. Harry reached out to her as she approached, captor at her heels, and she caught at his outstretched hand to tuck herself in between him and the Doctor, safety in numbers. "Doctor, it was the same as that other body we saw – it happened in minutes, Ola said, just a couple of minutes. I'd seen him, he was alive – and then he looked like that." She pointed to the first body they'd found, still lying where he'd fallen close to the impromptu graves of his colleagues.

"As fast as that?" The Doctor was intrigued.

"Strange how you failed to mention when questioned that you had an accomplice roaming loose still," Vishinsky observed. "How many more of you are there?"

"No more, I can assure you," said the Doctor in his mildest tone.

"Just as you assured us you were not responsible for these deaths?"

The Doctor opened his mouth and then closed it again, scratched at his head and wrinkled his noise, chagrined. "Ah. Yes. I do apologise for the omission, I can quite see how it must look, but given the hostility of the reception Harry and I received, I'm sure you can understand our reluctance to expose our friend to the same. Allow me to introduce Miss Sarah Jane Smith – Sarah, this is Commander Vishinsky. I'm afraid he's quite determined to blame us for the deaths of the survey team."

"Oh, but they aren't all dead," said Sarah. "I met one of them."

"What?" Vishinsky was startled. "You've seen Professor Sorenson?"

"Well, he didn't tell me his name, but he said he was a professor," Sarah began, and then stopped as a hatch slid open beneath the probe and a set of steps dropped down into position.

Flanked by armed guards, a man who could only be Captain Salamar strode down the steps in state. Startlingly pale with narrow-set eyes, sandy hair cropped close to his scalp, he was surprisingly young for his position of command. Not a tall man, he paused halfway down the steps to regard the assembled party down his nose in supercilious fashion, while his guards took up position around him, weapons at the ready.

"Vishinsky," he snapped. "Explain!"

dwdwdwdw

"Get your hands off me – let go!" Sarah squirmed away from a rigorous and intrusive search of her clothing and heard a scuffle nearby as Harry likewise protested, while the Doctor loudly complained that he was capable of emptying his own pockets, thanks all the same.

None of it did them any good. They were pushed, still struggling, back inside the survey team's base, roughly enough that Sarah almost overbalanced, caught at Harry's arm to save herself and nearly took him down with her.

"Do you ever get tired of being pushed around?" she grumbled as they steadied themselves, hanging onto one another for balance – and perhaps also, a little, for reassurance. All they'd done was respond to a distress call. It was infuriating.

"Frequently." It was the Doctor who muttered a response to her rhetorical question, sounding heartily fed-up yet resigned. It was rare to catch even such a fleeting glimpse behind his usual smiling façade, Sarah knew, but being shoved around at gunpoint when you were only trying to help was enough to wear anyone down, even him – maybe especially him.

"They are unarmed," Commander Vishinsky informed Captain Salamar.

"Well, of course we're unarmed." It was Harry's turn to grumble.

"Bring the prisoners forward," Vishinsky ordered, ignoring him.

Sarah glared at the guard nearest her, silently daring him to try pushing her again. A tall man with carefully coiffed hair patterned in brightly coloured stripes, he seemed to get the message, quirked an eyebrow in something that looked like sympathy and backed off. She stepped forward under her own steam with as much dignity as she could muster, Harry hovering protectively at her shoulder, which for once she didn't mind at all. They were all in this together – right up to their necks.

"Prisoners?" said the Doctor, smiling façade well and truly back in place, as if it had never slipped. "We're here to help, although you don't make it easy."

Captain Salamar eyed him down his long, thin nose – no mean feat, considering he was a full head shorter. "You are prisoners, charged with diverse acts of war against the subjects of Morestra."

Sarah couldn't believe what she was hearing.

"This is ridiculous," she protested, furious with them all, while the Doctor simultaneously countered the accusation with a firm, "Not guilty," and Harry argued, "We've already been through all this. We haven't done anything!"

"Silence," snapped Vishinsky, before adding, with a little more sympathy, "You will have your chance to speak."

"Thank you," said the Doctor with a decidedly sarcastic edge to his voice, incurring another glower from Salamar.

"This interrogation will be conducted in an orderly manner," the young captain insisted. "Failure to comply will result in your immediate execution."

He looked as if he meant it, as well. Sarah saw the Doctor open his mouth to argue some more and quickly stepped on his toe to shut him up. He subsided, looking mutinous.

"Not only have seven Morestran scientists been killed but now a member of my own crew has died. Your group is implicated in all these deaths with no other suspects." Captain Salamar had rather a high-pitched voice with a slight squeak to it, which undermined his attempt at judicial solemnity somewhat, but his conviction was absolute. "What have you to say for yourselves?"

"We haven't killed anyone!" Sarah glared at Ola Utoblo, who still looked distraught and was refusing to meet her eyes; she'd approached him to offer support and he'd turned on her, because he was afraid and upset and for no better reason than that. "Look, go and find the professor, if you don't believe me. He can tell you – I was with him when Bartrum was killed."

At least, she hoped the professor would corroborate her story; he was unstable enough that she wouldn't put it past him to have forgotten her completely.

"I should like nothing more than to find and de-brief Professor Sorenson," said Captain Salamar. "But there's no evidence beyond your word that he's even alive."

"He is – at least, he was when I saw him," Sarah faltered, suddenly doubtful, because anything might have happened to the professor since she left him.

A hand slid into hers and gave it an encouraging little squeeze – Harry, of course, trying to be reassuring. She squeezed back to return the moral support. Why wouldn't these people believe them?

"Then why did he not show himself to the search team?" Commander Vishinsky demanded – to the annoyance of his captain, who looked more than a bit disgruntled at having his interrogation hijacked.

"He hid from them," Sarah explained. "He was afraid – he didn't know who you were."

The Doctor, at least, was interested in her story. "What else did Professor Sorenson say, Sarah?"

"Well, he was babbling, confused – I think he was in shock. He said his work was important, too important not to continue. And he kept saying it wasn't his fault –"

"I'll ask the questions, thank you," Captain Salamar interrupted.

The Doctor ignored him completely. "What wasn't his fault? Did he tell you anything about the nature of his work?"

"Enough!" Salamar's voice was shrill with indignation. "I'm asking the questions here."

"Then ask the right questions, man," snapped the Doctor. "This girl is both the only person here to have spoken to Professor Sorenson _and_ the only person present with direct first-hand experience of the phenomenon that killed all these people, and you're too busy accusing her to hear what she has to say."

"You mean that funny turn I had when we first got here? You think it's connected?" A chill ran down Sarah's spine as she realised what he was implying. "It happened again later, as well, when I was with Sorenson – I couldn't move, as if I was being pulled from my body."

The Doctor regarded her sombrely. "You had a lucky escape, Sarah."

"There will be no more escapes," said Salamar, who didn't seem to be following the conversation at all. "I've heard enough of these lies and evasions."

"I'm not lying." Exasperation lent a hard edge to Sarah's voice. "Go and find Professor Sorenson if you don't believe me. He'll probably hide from you again, though," she ruefully added.

"I sent out one search team and found no trace of the professor, and a member of my crew is now dead," said Salamar. "I don't have such a large crew that I'm willing to throw away more lives on a wild goose chase."

"A commendable attitude indeed, Captain," said the Doctor with an approving nod and a broad smile. "Perhaps you might like to extend it to the possibility that my friends and I are innocent."

"The evidence against you –"

"Is circumstantial at best." The Doctor's voice became stern and authoritative. "You accuse us because we're here and for no better reason than that, an easy scapegoat to save you the trouble of investigating further. Captain Salamar, Commander Vishinsky, all our lives are in danger here and you're so busy throwing unfounded accusations around you that haven't stopped to examine the facts, so perhaps we might assume for the moment that my friends and I _haven't_ killed anyone and look instead at what the evidence is actually telling us."

"More deception, you're trying to cover your tracks," Captain Salamar accused, but Commander Vishinsky looked thoughtful now.

"I'm not so sure. Let's hear them out."

"Thank you, Commander." The Doctor smiled at him. "I knew you were a reasonable man – didn't I say he was a reasonable man, Harry?"

"The facts of the case, Doctor," Vishinsky dryly reminded him. "Our patience is not inexhaustible."

"Very well: facts. The fact is, we heard a distress signal, came to investigate and discovered the survey team just as you find it, and my young friend here had a close encounter with the culprit."

"You're saying that what happened to Bartrum could have happened to me." Sarah shuddered reflexively at the memory of that creeping, freezing sensation and the thought of what it could have led to, those shrivelled, wizened corpses. Was that how they'd felt in their final moments? How had she survived, twice, when they'd all died?

"I suspect it could happen to any of us, for as long as we remain on this planet," the Doctor grimly agreed.

"Well that isn't very reassuring."

"Reassurance won't protect us, Sarah, but forewarned is forearmed." He offered an encouraging smile that wasn't.

"I don't think four, six or even eight arms will help us if we don't know what we're up against!" Sarah retorted.

"Then we'd better start finding out. We do have a number of clues," said the Doctor, ignoring her feeble pun entirely, although Harry acknowledged it with a sympathetic grin and that guard with multi-coloured hair looked amused, over in the corner where his superior officers couldn't see it. "Your experience tells us the killer is both silent and invisible, and we know from Sub-ensign Utoblo's account that it strikes fast and drains the body completely in a matter of seconds – nothing human could do that."

"So you claim," Salamar stubbornly countered. "You could be using a new type of weapon."

"For what purpose? You already know we're unarmed," Harry argued. "What do you think is behind it all, Doctor?"

"I don't know," the Doctor admitted. "But I have some very nasty suspicions. Here's another fact: the survey team didn't all die at once; the dates on those graves suggest the deaths occurred over a period of weeks, yet it seems they neglected to call for help until it was too late. Why? Until we have access to their logs, we can only speculate – I don't suppose you've found the cause of the power loss yet, Technician Landa?"

The young woman called Landa had been quietly working away at the control console throughout all this, head bent over the exposed wiring beneath a panel she'd removed. She startled upon hearing her name and cast an uncertain glance to Vishinsky, rather than Salamar, for consent to disclose this information.

"No, sir, there's no sign of damage, all the connections are intact." Her voice was low-pitched and clear, her tone precise, a professional certain of her findings. "I'll need to check the external lines to be sure but I can't find any reason the solar cell shouldn't recharge normally once the sun rises – or any reason for it to have drained so completely in the first place."

"Another mystery – another clue," said the Doctor as Sarah glanced toward the window, which was just lighting up with the first rays of dawn. It had been quite a night. "Of course, if you linked up to the probe we'd have power to access the base computer now."

"Out of the question," Salamar snapped.

"Oh?" The Doctor lifted an eyebrow, curious, but didn't argue the point. "Then, if I may, I propose three lines of enquiry."

"_You_ propose?" Salamar was as snooty as a grand duchess. "You're a suspect, not an examiner."

"Well, with your permission, of course," the Doctor added with an exaggerated gesture of deference.

"The manual says…" Salamar began but the Doctor was having none of it.

"The manual can't help you here, Captain Salamar. You need to find Professor Sorenson. Sarah can help you with that. He survived when the rest of his team were wiped out. He'll be able to give us some real answers."

"You said three lines of enquiry, Doctor." Vishinsky seemed far more amenable than Salamar, regarding the Doctor intently, brow furrowed with thought.

"That's right, Commander. We need as much information as we can gather, and the survey team appear to have left very little physical evidence in this base. Restoration of power in order to study their computer records is the second line of enquiry – there may be a secondary cell in the stores here we can rig up, if you don't have any to spare – and the third, of course, is a post-mortem examination and bio-scan of the bodies. You have a medical officer, I take it?"

"Not as such. We have a fully equipped med-bay," Salamar warily replied, a suspicious look still in his cold blue eyes. "The KX9-06 has only a small crew complement; Vishinsky has first aider qualifications that were deemed sufficient for any accidents or illnesses that may arise on our mission."

"Oh, well this is your lucky day, then, Captain," the Doctor beamed. "My colleague Lieutenant Sullivan here is a doctor of medicine, more than qualified to carry out post-mortem examinations. Congratulations, you now have a medical officer…should you choose to accept our offer of help, of course." He regarded the young captain speculatively, wearing his most innocent, beguiling expression.

Salamar still seemed unsure, looked to Vishinsky as if for guidance, pursed his lips and narrowed his eyes, thinking hard, but at length nodded reluctant agreement.

"Very well. The girl will join a search team at first light. In the meantime, Technician Landa will oversee repairs here, and Commander Vishinsky will escort the doctor to med-bay and assist with the examination…"

"The Doctor? Oh, you mean that doctor." The Doctor gestured toward Harry, who lifted an eyebrow, amused. "Not this Doctor." And that, of course, was himself.

Harry might be amused by his antics, but Salamar was not.

"But let me give you fair warning: you remain under suspicion, all three of you," he sternly declared. "You will be permitted to assist in further investigation, but I will not allow my crew to be threatened. If you give any trouble – any at all – you will be summarily shot. Is that clear?"

"Crystal," the Doctor sourly replied.


	3. Chapter 3

**Part Three**

"'Lieutenant' is an archaic rank," Vishinsky remarked, apropos of nothing but with a note of challenge in his voice, as he led Harry through a maze of corridors aboard the space probe, which had much the same utilitarian feel about it as the survey team's base: metal floors, bare walls and security doors at every junction, all very functional, nothing of ornament whatsoever.

Harry opted not to rise to the challenge since, thirty thousand years down the line and all that, the man probably had a point.

"Well, I suppose I'm an archaic sort of chap," he said. Sarah certainly seemed to think so.

"You're from Earth, you say?"

"That's right."

"You're a long way from home. And your rank is military." Vishinsky paused halfway through a door and narrowed his eyes to regard Harry intently. "But your companions are civilian. How do the three of you come to be out here in deep space, so far from your unit?"

They were a good sight further from home and UNIT even than Vishinsky knew.

"I sometimes wonder that myself," Harry muttered under his breath, and then saw the look on the other man's face and hastened to deliver a more appropriate response. "I'm seeing the Doctor back to base, Commander…the long way, it seems. Er, is this it?"

He stepped past Vishinsky into the probe's med bay, which was large, bright and functional, full of unfamiliar equipment, the two corpses from the survey team base already here, brought on ahead by Salamar's navvies. It also contained something rather more unexpected.

"I say, that's the TARDIS!" Harry had known it had been captured, of course, but hadn't expected to find it here. He also hadn't expected to find it locked away behind some kind of forcefield: a shimmering, iridescent barrier.

"The box is yours." Vishinsky followed him across the room and watched, inscrutable, as he pressed his hands against the forcefield – simply had to try it, couldn't resist. It tingled to the touch, an impassable obstacle.

"Well, it belongs to the Doctor," said Harry, stepping back in defeat. They were going to have to prove their innocence to get it back.

Or find the control panel, perhaps.

This was Vishinsky's first sight of the TARDIS. His forehead crinkled, head tilting to one side to regard it with outright perplexity. "What _is_ it? Some kind of capsule – for storage, perhaps, is this where you keep your weapons?"

Was that honestly what he thought? Harry had thought Vishinsky was coming around to believing them, but clearly he was not yet convinced – the accusation was half-hearted, perhaps, but the suspicion remained nonetheless.

"Our vehicle, in point of fact." Harry felt rather as if he were walking on egg shells. How on Earth did one explain the TARDIS? He turned his attention to the corpses instead, hoping they might be simpler to deal with. He knew where he was with a corpse. "Er…shall we begin?"

Vishinsky seemed willing enough to leave the subject, for now. "We'll start with these two," he agreed with a nod. "Bartrum's body hasn't been retrieved yet."

His detachment was almost clinical, but anger at the loss of a crewman glinted in his eyes. Harry looked down at the two dead scientists.

"I'd rather a live patient, any day," he admitted. "Do you know their names?"

"Why?" Vishinsky was surprised by the question.

"Well, they were people once," Harry pointed out, remembering the graves they'd dug for their comrades, no one left to do the same for them. "We may have been too late to help them, but I should like to know who they were."

Vishinsky seemed to appreciate the sentiment. "According to the roster the female is Lake Alberg and the male Roman Aziz. Alberg was a geologist, Aziz the team's exographer."

"Lake Alberg and Roman Aziz." Rum sort of names these Morestrans had. "Right then…er…"

Looking around for the tools he'd need, Harry hesitated, suddenly realising this wasn't going to be quite as straightforward as he'd hoped. Archaic was the word, all right. An autopsy _should_ be a simple enough procedure – would be if this were anything even remotely resembling the hospitals he'd trained at or the sick bay he presided over at UNIT, thirty thousand years ago…but it wasn't. They called it a medical bay, but it was all computers and electronic gizmos and gadgets and whatnot – thirty thousand years of medical advances and not so much as an instrument tray anywhere in sight.

Vishinsky was already moving toward a rather fearsomely high-tech device at the head of the nearest cot, flicking a switch to activate the equipment. "A full bio-scan should give us all the information we need, don't you agree?"

"That was what the Doctor suggested," Harry recalled, heart sinking. He could examine a body and he could dissect a body, but the technology for a 'bio-scan' had not formed any part of his medical training!

Rum sort of a doctor he'd look, not knowing his way around a sick bay, when the position here was already tenuous and it wasn't just his own future at stake, but Sarah's and the Doctor's, too – Vishinsky barely believed their story as it was.

"Here we are then." Vishinsky waved for Harry to proceed.

If in doubt, the Doctor would bluff it out, always did. Not knowing what else to do, Harry crossed his fingers and sought refuge in hearty, pompous affability. "Well, this is your sick bay, Commander, I don't want to intrude. You go ahead and take the lead on this. I'll assist…"

dwdwdwdw

Captain Salamar waited for full daylight before sending Sarah out with a pair of guards to retrace her steps back to the plateau where she'd last seen Professor Sorenson, his manner high-handed enough that she felt her hackles rising and had to remind herself that she wanted the mission. Sorenson's evidence was crucial: both to clear her name and get to the bottom of whatever was going on here.

Daylight on Zeta Minor was dull and orange, casting a fiery glow across the gleaming metal surface of the space probe as they passed. Sarah wondered how Harry was getting on in there – hopefully better than the Doctor and Samina Landa were with their so-far futile efforts to restore power to the base, which had the Doctor in a high old dudgeon: torn between fascination with a problem that defied resolution and frustration that he couldn't find a solution anyway. He'd been up to his neck in cables when she left, muttering to himself about relays and back-ups, so absorbed in the problem he barely even noticed her go.

The guard called Wijaya turned to her as they stepped past the probe into the forest, his brightly-coloured head tilting quizzically and his dark brown eyes glinting with mischief.

"Lead on, o guide," he said with a saucy wink. "Watch out for ghosts!"

"Don't start," warned his colleague with the air of one who knew his ways of old, her blue-grey eyes scanning the tree cover warily. Wijaya laughed, stroking at the narrow black goatee that ran in a thin line down the centre of his chin and sideways along a strong jawline; he was handsome and he knew it, always the worst kind, his manner relaxed and teasing.

"Don't tell me you believe in invisible monsters, de Haan?"

"It doesn't matter if you believe in them or not," said Sarah, annoyed by his flippant attitude on top of everything else. "They're just as real, either way."

Wijaya shrugged, unconcerned. "I'll believe it when I see it."

De Haan was a tall, athletically-built young woman with thick chestnut hair drawn back into an untidy chignon, a few wispy curls straying loose around her temples. She rolled her eyes eloquently and caught Sarah's eye. "That's the point, isn't it – if they're invisible you won't see them. Not till it's too late."

"Oh, so you do believe in ghosts," Wijaya teased as Sarah led the way deeper into the forest, trying to remember the right direction to take.

"I believe something killed Bartrum and those scientists," de Haan retorted, and he sobered at once, whether at the thought of ending up like that himself or at the reminder of the crewmate they'd lost.

With sunlight filtering through the tree canopy, the vines and fungi lost their luminescent glow, but the mud underfoot remained just as viscous. Sarah gritted her teeth and tried not to think about the nice solid roads and pavements of London, where the Doctor was supposed to have taken them; she'd known they were never going to go straight there and had delighted in the thought of it, the excitement of setting out for an unknown destination and exploring a new world. Boggy ground and spoiled boots were a small price to pay…even if it didn't feel that way after spending half the night trying not to get stuck in the mud.

Staying alive, now, and keeping everyone else alive, solving the mystery – that was the thing.

Behind her, de Haan picked her way along stoically enough while Wijaya's studied air of light-hearted nonchalance gradually faded to disgruntlement.

"So much for a nice boring charting mission," he grumbled just as Sarah heard a sound up ahead and stopped dead in her tracks, trying to listen.

"Did you hear that?"

"One of your ghosts?" he teased.

"I don't think so." Wijaya might think it all a big joke, but Sarah knew otherwise. There was no crackling sound, no chill in the air, this wasn't the same thing she'd experienced earlier, but she'd definitely heard something. "There's something moving – coming this way."

De Haan pushed alongside her, be-freckled snub of a nose crinkling as she frowned in concentration, head tilted to listen. "Over there!"

She stepped forward, reaching for her gun, and Wijaya too was suddenly all business, humour and scepticism forgotten as he moved in front of Sarah like a human shield, weapon in hand, shouting, "Who goes there?"

They waited, tense, listening to the rustling of foliage and slapping of footsteps through thick mud, growing closer and closer…until at last a bulky figure swept into view through the trees.

"'Who goes there' – how dare you! Who goes _there_?"

Sarah breathed again. "Professor Sorenson! It's all right, it's the professor."

"And who might you be?" he grumbled with a scowl.

"It's Sarah, Professor. Sarah Jane Smith – don't you remember?" She felt a pang of doubt – if he didn't remember her, failed to back up her story, would that place her back in the firing line for Bartrum's death? Would the rescue team fall back on accusing the easy suspects once more and give up the investigation completely – until more people died?

Sorenson squinted at her.

"Oh yes. You," he said, and she let herself relax again. "But what's all this? Where've you all come from?"

"Senior Ensign Carly de Haan, Professor Sorenson – this is Ensign Eslam Wijaya." De Haan stepped forward, holstering her weapon, and held out a hand in greeting. "We're with the space probe KX9-06. We were diverted to check up on your team, Federal Council were concerned that contact had been lost. Are you all right?"

Sorenson peered vaguely at her outstretched hand but did not take it.

"Then this is a rescue," he muttered to himself. "Not here to steal. Yes, yes that's right, that's what was needed. I'm ready now."

De Haan was confused by this rambling reply. "This is a rescue mission sent by Morestran Federal Council, yes. We're here to take you home – are you all right?"

"Oh yes," he repeated, and he did seem to be more lucid than when Sarah had seen him last, even if his attention was rather scattered still. "Yes, the days are quite safe."

"We need to escort you back to base, Professor," de Haan continued. "Captain Salamar wants to talk to you about your team."

"Team…my team." Sorenson seemed almost to shrink into himself and blinked at her in apparent confusion. "Aren't they there?"

De Haan was taken aback. She cast worried side eyes toward first Wijaya and then Sarah, and carefully asked, "You think your team is at the base, Professor?"

"He knows they aren't," Sarah murmured, remembering those graves, his reaction when she'd spoken Evan Danziger's name aloud. He'd told her there was no one left but him, he couldn't have forgotten. Could he simply not face the truth in the cold light of day?

He twisted his hands together in agitation, muttering, "Alberg is there – should be there – Aziz returned to base, he – he was suffering from fatigue. He'll be fine now."

"When did you last see Aziz?" Wijaya pressed. "What happened to the others? There were eight in your team."

De Haan shot a warning glance at him, hissed, "Leave it to the captain, Eslam," but it was too late, Sorenson became deeply distressed.

"We've had difficulties. Conditions are hard," he muttered, wringing his hands, his gaze darting all over the place as if he couldn't bear to make eye contact. "We've lost some…we lost them…but the important thing is the mission has been a success. We found what we came to find." He blinked and shook his head distractedly. "Yes. No, its fine, the mission was a success. It's not far."

He plunged away, heading in the direction they'd just come, back toward the base, and all they could do was follow.

dwdwdwdw

The bio-scanner and associated technology in the KX9-06's medical bay was astounding, beyond Harry's wildest dreams – in fact, trying not to exclaim with delight at what it could do was almost harder than surreptitiously prompting Vishinsky to show him the ropes without giving himself away.

Almost.

He rather thought he might actually be pulling it off, observing and learning…until Vishinsky asked him to pass the neurolyte probe and he had no idea what that was.

Harry panicked, selected a tool at random more in hope than expectation, knew at once that he'd chosen wrong and tried to bluster his way out of the mistake…but it was no good.

"You're a terrible liar, Lieutenant," said Vishinsky, deadpan, and just like that the jig was up.

It occurred to Harry that his mother would have been delighted to hear this assessment of her only son, but for a professional working in the security services, sometimes called on to operate undercover, it was rather a damning indictment.

"Yes," he said with a sigh. "I know."

Vishinsky had a marvellous poker face, utterly unreadable.

"I can't make you out, Sullivan," he said, steely gaze fixed on Harry's face. "You know your medicine, right enough, but you can't tell a neurolyte probe from a dermal bond unit, can you?"

The Doctor would have got away with it, Harry was sure – but then again, the Doctor would have known where he was with this technology to begin with, no pretence necessary. He still didn't see what else he could have done but play along, in the circumstances, but also didn't know what he could say now that wouldn't compound this failure, that would convince the commander of their innocence and benign intentions.

Sarah and the Doctor were relying on him. And the truth was all he had.

"I'm sorry, Commander," he said. "You're right. I am a doctor…but your technology is a bit beyond me, I'm afraid."

Vishinsky's eyes narrowed still further. "I thought you said you were from Earth."

"I am from Earth," Harry helplessly insisted. Just not the Earth Vishinsky would assume.

Vishinsky studied him for what seemed an age, brow crinkled in thought…but then shrugged as if this was all he'd needed to hear.

"I knew Earth was a backwater, but I hadn't realised Morestran medical technology had deviated so far from central standard," he said. "Why not simply say so from the start?"

Was that it? Harry could have kicked himself – if a technological divide between Earth and the Morestran Federation was so readily believed, he needn't have put himself through all this in the first place.

"I'm sorry," he said again, with chagrin. "If you ask Sarah, she'll be quite happy to tell you what an idiot I am. I'm afraid I panicked rather when I saw all this equipment, after the Doctor had told you I could help. You already suspected us of murder…"

Vishinsky snorted, looking almost amused.

"I don't know who you people really are, Lieutenant, or what you're doing here, but you didn't kill these people. I don't know what did, but that Doctor of yours is right." He turned back to the corpses, shaking his head. "Nothing human could have done this."

"No." It came as a relief to know that at least someone believed them. The Doctor had said Vishinsky was a reasonable man and this was what he meant – Harry rather envied that ability to judge a fellow so accurately, within minutes of meeting him.

"You may not be familiar with our technology, doctor," Vishinsky added, "But you've made more sense of these findings than I have. So let's finish this."

dwdwdwdw

Sorenson possessed a rare turn of speed, Sarah already knew that from their earlier meeting, and again she had to trot to keep pace with him, wishing for longer legs, as he dashed out of the tree cover and charged across the glade, barely sparing a glance for the probe as he passed, calling loudly for his former teammates.

The Doctor was outside the base, perched on tiptoes on a narrow window ledge to work at full stretch on the connections to a panel on the roof. Distracted by the sudden tumult, he lost his footing and fell, landing on his back in the scrubby underbrush that surrounded the building. Already running at full tilt after Sorenson, Sarah changed direction mid-stride.

"Doctor!"

The Doctor, however, was not the slightest bit interested in being helped back to his feet…or, indeed, in the minor fact of his having fallen in the first place.

"Was that Sorenson?" he demanded, lunging toward the door. "Quickly, Sarah!"

Hurrying into the base, they almost ran into the backs of de Haan and Wijaya, who'd stopped dead because Sorenson had stopped dead, staring numbly at Landa, who was working at the control panel, and Salamar, who was hovering fussily at her shoulder.

"Aziz," Sorenson whispered. "Alberg. Where are they?"

Salamar eyed him severely.

"Professor Sorenson, I presume," he brusquely observed. "We've been waiting to speak to you."

Sorenson's mouth opened and closed a few times.

"They're gone," he managed at last, half-turning, his haunted eyes darting around before focusing on Sarah with something that looked like mute appeal. "All gone."

"I know. I'm sorry." She impulsively pushed forward to take his hand, full of sympathy for his broken state.

"Can you tell us what happened to your team, Professor?" the Doctor gently asked.

Sorenson twitched. "Alberg was here, she was compiling reports. Aziz returned to base…"

He faltered and trailed off, and Salamar huffed with frustration.

"Professor Sorenson, I am Captain Salamar of the space probe KX9-06," he rapped out in cold, brisk tones. "Morestran Federal Council were concerned that contact with your team had been lost –"

"So you were sent to check on us," Sorenson unexpectedly finished for him, indicating de Haan. "She told me."

Salamar was flustered by the interruption – and was annoyed by his fluster, visibly frustrated by his inability to impose his authority and control on the situation. "Professor, we arrived to find Aziz and Alberg dead alongside the graves of the rest of your team. You are the only survivor. Can you explain?"

Again Sorenson's mouth opened and closed, like a goldfish gasping for air.

"The mission. My mission…" he stammered at last, blinking. Then he rallied, an almost manic gleam in his eye. "My mission is complete, Captain – the breakthrough was made only in these last days, a discovery of tremendous importance. We found what we came to find."

"And what was that, Professor?" the Doctor asked with great interest. "What were you looking for? What did you find?"

"Don't answer that question," Salamar immediately snapped, eyeing the Doctor distrustfully. "Perhaps we might return to the probe, Professor, and continue this interview in private."

"What? No, wait," the Doctor protested. "I must speak to the professor, it's vitally important that we find out –"

"No, Doctor," Salamar insisted, a glint of vindictive satisfaction creeping into his cold blue eyes. "Your assistance with the professor's de-brief is not required. Come this way, Professor Sorenson."

He ushered the bewildered Sorenson away with a final glare at the Doctor, who sighed.

"The fool," he growled under his breath, hurrying after them. "Captain Salamar, I must talk to the professor – you don't understand how vital it is."

"No, Doctor, you don't seem to understand how vital it is," Salamar snapped. "Professor Sorenson's mission here is top secret – certainly not for the likes of you. You are on probation, if you recall, and your innocence has not yet been proved. You will remain here and continue working – stay with him, Landa. De Haan, go to med bay and tell Vishinsky I want to see him in my quarters immediately. Wijaya, with me."

He swept Sorenson away, de Haan and Wijaya at his heels.

The Doctor stared after them, looking thoroughly disgruntled. "Do you know, Sarah, there's just no helping some people. Did Sorenson tell you anything?"

"Not a lot," she admitted. "Nothing you haven't heard for yourself just now."

His elastic face contorted in a grimace of frustration. "Well, perhaps the survey team's logs will prove a little more enlightening. I think we're almost there now. Did you find that mag-lock coupler, Samina?"

Landa stepped forward with a tool in her hand and a thoughtful, closed-off expression on her face. The Doctor took the tool and clambered back up onto the window ledge to resume his work, and it was Sarah's turn to sigh in exasperation, wondering what he expected her to do now. Stand around and watch him work, probably.

No chance.

"I'll go and see how Harry's getting on, then, shall I?"

There was no reply, not that she'd expected one. Typical Doctor: lost to the world when his head was buried in a project. Sarah poked her tongue out at his back and headed for the probe, wondering how she was actually going to find her way to the medical bay to check up on Harry.

The problem was solved almost immediately when she saw that de Haan had stopped just outside the probe to re-fasten a boot.

"Mind if I tag along?" Sarah brightly asked.

De Haan was dubious. "I don't know if I should…"

"Oh, go on," Sarah wheedled. "What harm could I possibly do?"

De Haan tilted her head and pursed her lips, then suddenly smiled, jerking her head for Sarah to follow her aboard. "Come on then, before the Captain sees you."

"He's got enough on his plate without worrying about me," Sarah diplomatically agreed, not liking to say that he seemed a little out of his depth, although from the look on her face de Haan might agree with that sentiment.

"This is not what any of us were expecting from this mission," she carefully replied, leading the way along a series of dull, featureless hallways.

"You said you'd been diverted," Sarah remembered. "Was it far out of your way?"

"Pretty far," said de Haan. "And hard rations all the way; we're not really provisioned for a push this deep, but we were the nearest, so. No one comes this far out if they can help it – there's no telling what might be out here."

_No telling what might be out here_. Did that mean…? "You believe us, then?"

De Haan regarded her solemnly. "Do I believe that an unexplored planet on the far edge of the known universe might hold hidden dangers? Yes, Miss Smith: I do."

"I wish your captain felt the same way," Sarah told her with feeling. "It's Sarah."

De Haan smiled. "Carly. Here we are."

Following the other woman into the medical bay, Sarah was relieved to find that there was nothing grisly on display. The room was light and bright, packed with computers and all kinds of high-tech equipment – not the slightest bit like Harry's sick bay back at UNIT, yet he seemed perfectly at home, head bent over a display on a screen, discussing the read-out with Vishinsky, so engrossed that neither noticed the new arrivals at first.

Strangely enough, the TARDIS was also there, every bit as incongruous as it had looked in the Doctor's lab back on Earth. Sarah stared at it in surprise as de Haan delivered her message.

"Sorry to disturb, sir – we've located Professor Sorenson. The Captain would like you to join them in his quarters."

While Vishinsky grouchily responded, Harry noticed Sarah for the first time and leapt to his feet with a big smile, hurrying over to greet her. De Haan departed with a friendly grin and Vishinsky, looking harassed, scuttled off to see what the captain wanted, muttering that he wouldn't be long, but Sarah was still more interested in the TARDIS, locked behind a shimmering barrier – fat lot of use it'd be to them in there.

"So that's where it went," she said as soon as she and Harry were alone.

"Is that a forcefield?"

"Quarantine field, according to Vishinsky," he cheerfully replied, in the rather pompous tone he liked to use when he was pleased about knowing something she didn't. "I believe it's operated from one of those panels over there, but they've not shown me those controls, obviously."

"Obviously. The Doctor would know. If he was here we could just jump back in and go: leave them all to it," Sarah said, knowing it was never going to be that simple and asking herself if she'd ever really want it to be. There was a mystery here, just waiting to be solved, and she wanted to know what the answer was.

"That'll be the day," Harry retorted with a rueful grin.

"Won't it just! Well, at least we know where it is when we need it. How are you getting on with all this…?" She waved her hands around the room, failing to come up with an appropriate description for all this, "This."

It was the wrong question to ask. Harry promptly started bouncing all over the place, showing her various pieces of equipment and trying to explain what they did, positively bubbling over with enthusiasm for the marvels this advanced medical technology was capable of.

Sarah laughed. She didn't often see this side of him – it was rather sweet, even if she barely understood a word. "Harry, are you trying to tell me you actually know how to use all this?"

He flashed a grin that was pure schoolboy. "Of course not, old thing – but Vishinsky does. Look, we've nearly finished here. Tell the Doctor I'll pop back over to update him in a jiff."

With Vishinsky now otherwise occupied, Sarah might have offered to help, except she'd already had her fill of playing nurse to Harry's doctor back on Nerva Space Station. She took his advice instead, swatted his arm for the 'old thing' and headed off…only to find a guard at the main exit, who glowered at her on sight.

"You're not supposed to be wandering around."

"Really? No one told me," Sarah pertly replied. The man was not amused.

"Where do you think you're going?"

"Over there." She pointed out through the open door. "Back to the base."

"Quickly then – and stay there," he snapped, standing aside to let her pass, and when she glanced over her shoulder she saw that he'd gone straight to a wall-mounted communication device just along the hallway – informing the captain, perhaps. Whatever happened to that cooperative spirit of investigation?

There was a chill in the air as she stepped outside the probe, her breath misting in the air despite the warm sun riding high in the sky. She stopped in her tracks expecting the worst, goose-bumps pricking at her skin and breath catching in her throat because she knew now, she'd seen those corpses…

But there was no crackling sound this time. The chill faded.

Sarah breathed again. Had something passed by without attacking? Or was her imagination playing tricks on her?

Better safe than sorry. She hurried on into the base, calling out, "I think we've lost Harry to medical science," as she entered, and then saw that the Doctor had the computer working at last. "Hey, you've got the power back!"

"Well yes, but then again no," he rather vaguely replied, and then completely failed to elaborate, attention focused on the screen before him.

"We tried connecting a spare power cell from base stores, but found it had also been drained. Both are now linked in and charging," Landa helpfully explained, hovering at his shoulder looking brisk and efficient. "But not to anything like full capacity. There's no fault that we can find, if I didn't know better I'd say something was drawing the power off –"

"Something _is_ drawing the power off," said the Doctor without looking up. "But we can worry about that later. By piggy-backing the two and boosting the gain there's just enough charge now to give us access to the mainframe and that's all we need. What was that about Harry?"

"He'll be over in a minute," said Sarah, peering over his shoulder for a look at the screen that had him so engrossed. "What've you found?"

"The answer," said the Doctor, looking grim. "Although of course these poor souls didn't know it at the time."

dwdwdwdw

Sending Sarah back over to the base without him had been a mistake, Harry realised when he tried to find his own way back and became hopelessly lost the moment he set foot outside of the medical bay. Vishinsky had been talking when they came, so he'd not paid much attention to the route – had they approached from the left or the right…?

"Oh good job, Sullivan," he muttered to himself, looking up and down the featureless corridor and spotting no landmarks for navigation whatsoever. First the tangle over unfamiliar medical equipment and now this – fine work he was making of the mission!

"Did you cut him open?"

Harry startled at the unexpected question and span around to see the young man who'd captured Sarah standing along the hallway eyeing him moodily.

"Sorry, old chap, didn't see you there. It's, er…" Dash it, what was the name again? "Sub-ensign Utoblo, isn't it?"

Utoblo nodded. "Leo Bartrum," he said, a note of urgency in his voice. "We brought his body back. Did you cut him open?"

Another haircut that would have been strictly non-regulation in Harry's day, and the lad barely looked old enough to shave. You knew you were getting old, Harry told himself from the lofty vantage point of approaching 30, when recruits started to look so dreadfully young.

"No," he said and watched as Utoblo's taut posture relaxed very slightly, relief coming into his eyes. This mattered to him. "No, there was no need. He was a friend of yours, was he?"

"You could say that." The lad studied his shoes. "I don't like to think of him cut open in there."

_That_ sort of friendship, perhaps – Harry'd attended an all-boys boarding school and then joined the Navy; he'd grown rather good at spotting the signs. He fumbled for what to say now. "Er…would you like to see him?"

Utoblo shook his head, lips pressed tightly together. When he spoke his voice was low, tightly controlled. "I already saw him. In the woods. Did your people do it?"

He'd been quick to accuse Sarah earlier but seemed more upset than hostile now.

"No," said Harry.

"Do you know what did?"

"I'm afraid not." Harry did, on the other hand, suddenly see a way out of his current predicament. "I do have test results, however. Perhaps you might show me back over to the base…?"

Having a guide made all the difference. They made it to the exit in no time and stepped outside to find the Doctor having a blazing row with a guard at the door, Sarah at his shoulder looking annoyed and the technician called Landa stood to one side, determinedly not getting involved.

"For heavens' sake, man," the Doctor boomed. "You don't understand –"

"I understand my orders," the guard stolidly replied. "You people are not to move around."

"Since when?" asked Utoblo from behind him, all innocence and bewilderment – not up to speed on the latest orders, clearly.

The guard hadn't heard them approach and startled.

"Since the captain said…" He broke off as he spotted Harry and all but growled in exasperation. "That one's not supposed to be wandering around either!"

"Then perhaps you should have put a guard on the infirmary," Harry mildly suggested, wondering what had gone wrong now. "What's going on?"

"Yes, why are we being penned up?" Sarah hotly demanded. "We haven't done anything wrong, we're been helping with the investigation – what's changed?"

"The captain's been having a cosy little chat with Professor Sorenson. I imagine that's what's changed," the Doctor darkly remarked, and Sarah frowned, turning puzzled eyes toward Harry, who couldn't honestly say he was any the wiser than she was.

"What difference does that make? We have new information," she told the guard. "We must see the captain."

"The captain's busy."

"He'll be busier still if he doesn't make time to hear what I have to say," the Doctor warned.

"He's not to be disturbed, he gave strict orders."

The Doctor eyed the man appraisingly. "What's your name?"

"Harlow Ponti," replied the guard, warily, as if he feared it may be a trick question. A tall man with a thin, wiry build and a neatly trimmed beard, the rich brown of his skin contrasting starkly with the bright white trim of his uniform, he was smart, officious and unwilling to budge an inch, because orders was orders. Harry knew the type well.

"Mr Ponti, eight people have died on this planet and there will be more deaths to follow if we don't act now," said the Doctor, his most charming, persuasive tone laced with urgency. "Now, you can sit back and allow that to happen, and comfort yourself that you followed your orders to the letter…or you can open your mind and try thinking for yourself. Make a choice. Take a risk that might just save the lives of your comrades – perhaps save your own life. Call the captain. Tell him we need to speak to him, urgently. We'll just wait right here."

He made a big show of planting his feet on the ground and stuffing his hands into his pockets to demonstrate that he had no intention of budging so much as an inch until his request was granted.

Ponti glowered at him morosely but at last let out a sigh of defeat.

"I can call through to Command and leave a message for when the captain is free," he suggested, and stomped back into the probe wearing a disgruntled expression and the long-suffering air of a man who felt deeply put-upon.

Harry looked to the others, confused still, because they'd all agreed to cooperate, hadn't they? "What's brought all this on, then?"

"Sorenson's a fool," said the Doctor, as if this explained everything. He began pacing impatiently around. "No sacrifice too great in the pursuit of glory. Never mind the lives when there's mineral wealth to be harvested, a new resource to fuel a depleted homeworld – and a hero's welcome for the man who made it possible, working on while his team were slaughtered around him."

"But he was so upset," Sarah protested.

"Guilt," the Doctor snarled. "It's all there in the log. He forbade his team to call for help because he thought he was onto something – by the time Alberg broke rank it was too late. Never mind the implications, the consequences – blind idiocy – and now he has the captain's ear, and Salamar's fool enough to fall for it."

This last was almost spat at Landa and Utoblo, neither of whom seemed to know what to do. Right or wrong, Salamar was their captain, after all.

"Fool enough to fall for what, exactly?" Harry began to ask, before the other thing the Doctor had said registered. "Hold on, what was that about minerals?"

"That's what this is all about, apparently," Sarah explained. "It's what the survey team were looking for – what they _found_."

It also struck rather a chord. Harry held out the fistful of print-outs he'd brought over, courtesy of Vishinsky, who'd shown him how.

"The thing is, you see, we picked up some sort of residual mineral trace on a kind of tissue profile of the victims," he explained, sure it must be relevant somehow – too odd not to be. "Marvellous technology, I must say. Wish we had it in my day!"

The Doctor took the papers, teasing, "You're glad you came now, aren't you, Harry?" with a cheeky wink.

Harry opted not to rise to the bait.

"Traces left at a micro-cellular level," the Doctor mused, leafing through the report with Sarah peering over his shoulder. "That's very interesting…"

"Couldn't identify the substance, though, I've never seen anything like it – and neither had Vishinsky," Harry added, well aware that, as a native of this time, Vishinsky's inability to identify the mineral traces carried far more weight than his own.

"I'd be surprised if you had," said the Doctor.

Harry waited for a moment to see if he'd elaborate, but nothing seemed forthcoming so he continued his report. "The victims died of dehydration and blood loss, as suspected, complete extraction of all bodily fluids, even the bone marrow – but we couldn't determine the cause. There's no damage to the organs, no contusions, no puncture marks, nothing to indicate excessive heat or pressure. It's almost as if they were…well, freeze-dried."

"_Freeze_-dried?" Sarah shivered reflexively.

"All right there, old thing?" Harry promptly asked without thinking and then held up his hands in penitence, _mea culpa_, when she narrowed her eyes at him in silent protest at the nickname.

"That's what would have happened to me," she said with a shudder, distress visible in her ever-expressive face. "It's what _started_ to happen to me, both times – I felt so cold, as if I were frozen to the spot – and there was something _there_, I know there was, pulling me out of myself."

"And that's what happened to Bartrum?" Landa shot a knowing glance at Utoblo's stricken expression.

"It's what happened to all of them," the Doctor sombrely confirmed.

"But how – why?"

He brightened. "I'm glad you asked, Samina. Tell me, what's your understanding of extra-dimensional cosmology?"

He made it sound rather as if this were something that everyone ought to be fully up to speed on. Landa blinked at him. "I'm a technician. I repair machines – I leave theology to the Lamas."

"Not theology, _cosmology_: the study of universes."

"Universes plural?" Harry was lost already – just the one universe, with everything in it, seemed more than enough to him.

"Yes, Harry: universes plural." The Doctor began to pace again, arms waving in expansive gestures to illustrate his point, eyes blazing with the thrill of scientific discovery. "Hundreds of universes – millions of universes – stacked up against one another…and over one another and under one another and alongside one another and _through_ one another. Universes existing in dimensions we can't begin to comprehend, that can never meet and never cross…and yet sometimes, just sometimes, here and there, someone will stumble on a thin point: an impossible place where two incalculably unlike dimensions _almost_ touch."

Stunned silence followed this impressive speech. Utoblo looked dumbfounded, Landa's eyes had gone wide and Ponti had reappeared at the entrance to the probe, gun in hand to bar their way but listening curiously.

Harry looked at Sarah, who seemed no more the wiser than he was.

"And that's where we are?" she asked. "At a thin point between universes?"

"Yes," said the Doctor with a decisive nod.

"You'll never convince the captain," Landa flatly declared, shaking her head.

"Ask not whether Captain Salamar believes in outer-dimensional beings," he loftily replied, adopting a sepulchral tone. "Ask rather, do those outer-dimensional beings believe in him?"

Harry tried to understand. "Let me get this straight. You're saying that this place is at the boundary between two universes and these deaths were caused by some kind of…creature from the other side?"

"In a nutshell," said the Doctor with a nod. "Yes."

Utoblo spoke up now, frowning. "But how does a creature from another universe kill people in this one? That doesn't make sense."

"A good question," said the Doctor, but before he could answer it, Captain Salamar appeared at the entrance to the probe, flanked by armed guards, a sheepish-looking Vishinsky at his shoulder, and a man Harry hadn't seen before at his heel, wild-eyed and haggard – the enigmatic Professor Sorenson, presumably. "Ah, Captain, about time, we need to talk," the Doctor began, an urgent bite to his determinedly jovial tone, but Salamar cut him off.

"Thank you, Doctor; your input is no longer required. Professor Sorenson has explained everything I need to know."

"He has? I doubt that. Captain, you must listen to me, we're all in the most terrible danger, for as long as we remain on this planet –"

"Then you will be delighted to hear that we are leaving," Salamar smartly interrupted. "Just as soon as we've loaded up the professor's cargo."

"What cargo?" As a note of trepidation entered the Doctor's voice, Harry exchanged uneasy glances with Sarah. The Doctor hadn't exactly explained his theory, but if he thought it worth worrying over, it was worth worrying over.

"That's classified information," Salamar snapped even as Sorenson pushed forward, calling out, "My samples, my research – rock formations on the very fringe of the universe, a new and inexhaustible source of energy –"

Salamar glared at the man, too late.

"Yes, I thought as much. A totally unknown mineral, something entirely new and undiscovered, a thing of beauty, and all you see is fuel, potential for profit – but you mustn't," the Doctor angrily protested. "Captain, you can't. Don't you realise? The deaths began when the survey team started their tests on the crystalline substance they'd discovered here, attempted to refine it –"

"Coincidence," Sorenson defensively claimed.

"Vengeance," the Doctor countered. "Something here doesn't want you to have those crystals. It will kill to protect them – already has."

"And who could have a better motive than a rival seeking to steal the Professor's work and claim credit themselves?" Salamar's pallid face flushed, his cold blue eyes flashing with moral indignation. "A rival such as you, Doctor. What other purpose could you possibly have here? Guards!"

Accused again – the turnaround was startlingly abrupt. As the guards surged forward, guns at the ready, Harry tried appealing to Vishinsky, who'd seemed so reasonable earlier and knew damn well that they hadn't killed anyone.

"Commander, you know we had nothing to do with those deaths, you've seen the evidence."

But the commander only shook his head. Shame and regret were written all over his face yet he refused to speak out against his captain's decision. "It's out of my hands, I'm sorry."

As the guards began to push and shove them back toward the base, the Doctor twisted free and lunged at Salamar, caught at his arm, still trying to convince him of the danger. "Salamar, you must listen –"

A flash from someone's gun and he collapsed where he stood.

"Doctor!" Sarah's cry of horror rang in Harry's ears as he instinctively surged forward, hardly even knowing what he was doing – the Doctor was down, injured, he had to check –

Another flash of light – and the world went dark.


	4. Chapter 4

**Part Four**

Sarah couldn't keep still.

It would be dark again soon, the light was already fading, and the probe's crew must have finished loading by now, surely, she hadn't heard anything for ages, time was running out – and here she was stuck in the survey team's bunkroom with two unconscious lumps…

She carefully checked the two unconscious lumps again to reassure herself that they were both still alive and breathing steadily, and then resumed her pacing about the room, as far as the chain tethering her to a bunk would allow, worrying at a fingernail as she went. She'd found some ration bars on a shelf and nibbled at one to ease her growling stomach, but could hardly bring herself to swallow – too jumpy in case something happened and too anxious that nothing was.

The enforced idleness of captivity did not grow easier with practice – worse, if anything.

At last the Doctor began to stir and she hurried to him, hovering anxiously as he groaned and mumbled to himself a little before his eyes abruptly snapped open.

"Someone shot me!" he indignantly declared, sitting bolt upright – and then grimaced, grinding the heel of a palm into his eye.

Sarah had seen that reaction before, always after he'd been stunned. "Headache?"

"Never mind that." Brushing it off, like he always did, because he liked the universe to think him invulnerable and always had larger concerns on his mind, he shuffled over to the next bunk, where Harry was just beginning to twitch, and began patting at his face to rouse him. "Is that ship still here?"

"Yes," Sarah assured him. "It's all gone quiet, but they haven't taken off yet."

"Then there's still a chance. Wakey-wakey, rise and shine, Harry. Come on, man, look lively – we've an escape to be getting on with."

Sarah had long since scoped out the possibilities on that front and headed for the door while the Doctor hauled a groggy Harry to his feet.

"Psst," she loudly said to get their attention, and then pulled the door open. "It isn't locked."

The Doctor beamed at her in delight – but then looked worried. "Power's drained again, more like."

"Not that it's done me any good up till now," Sarah sighed, rattling the length of chain attaching her wrist to the bunk; she could reach to open the door, but not pass through it. "Why else do you think I've been sat here twiddling my thumbs waiting for you two sleeping beauties to wake up?"

She regretted her use of the word 'beauties' immediately as Harry flashed that schoolboy grin again, bleary-eyed still but awake enough to be mischievous. Then the Doctor produced his sonic screwdriver from the depths of an inner pocket, made short work of three sets of shackles, and they were away.

As soon as they set foot outside the base, Sarah knew something was wrong.

"It's cold." Not the freezing chill of an attack, but cold enough to be noticeable, colder than this planet had been ever since they arrived – and the atmosphere felt wrong, strangely pressurised, with something almost like a humming sensation that was just on the edge of audibility, as if the air itself were vibrating. "What _is_ that…?"

"We're running out of time," said the Doctor, leading the way across the glade looking grim.

She could have kicked him for being so cryptic at a time like this, had to trot to keep pace with him. "Running out of time for what…?"

The sentence died on her lips. Across the glade, Commander Vishinsky and a small team were just emerging from the forest, staring at them in disbelief.

"How…?" Vishinsky began, astounded to see prisoners on the loose, and then he went for his gun. "Hold it right there!"

All of them had their guns at the ready, even the ones they'd talked to, who'd seemed to understand, who should know better. Sarah slowed at once, catching at Harry's arm to hold him back, because there'd been enough shooting already and she was sick of this now, furious with these idiots for their stupidity and close-mindedness …but the Doctor simply charged onward, arms in the air to show that he meant no harm, and what could they do but follow?

"Commander, please, you must listen to me!" he called out.

"So you can tell more lies?" Vishinsky had seemed almost sympathetic earlier, but now he just looked tired – disappointed, even. To some of the crewmembers with him he snapped, "Get that kit stowed away," and to the Doctor he demanded, "What have you done to our ship, Doctor? What can you hope to gain now by this sabotage?"

"Sabotage?" The Doctor was flummoxed by the new accusation, which wasn't something you saw every day. Then his face cleared and he slapped a hand to the side of his head. "Draining power from the probe – of course, I should have guessed. Commander, that isn't sabotage, at least not of our doing. The same thing happened to the survey team, the base has been losing power all day, faster than the solar cell can recharge – Technician Landa here can confirm."

He gestured toward Landa, prim and sedate at the commander's elbow, and she nodded, just a hint of reproach in her voice. "It's true, Commander – I did say so in my report."

"Listen, you must take your people away from this planet," the Doctor urged. "As soon as you possibly can –"

"That's the plan," Vishinsky growled.

"_Without_ attempting to take Sorenson's crystal collection with you," the Doctor continued. "They won't allow that."

"They who? Doctor, I'm growing tired of these games."

"The creatures that live on this planet, of course. The creatures that killed the survey team and your crewman, the creatures who are all around us _right now_. They exist on another plane, unknowable and untouchable, but they can reach into this dimension, they've more than demonstrated that, and they know, Commander – they know you mean to leave and they know what you mean to take with you. Can't you feel the disturbance in the air?"

"There's a storm brewing," Vishinsky stubbornly insisted. "We'll leave before it hits."

"Oh, open your mind, man – use your intelligence!"

Harry chimed in now, arguing, "You said yourself nothing human could have caused those deaths," and then Sarah noticed Wijaya, at the back of the group, frowning and glancing around, the air of disinterested nonchalance he'd affected earlier nowhere now to be seen.

She sidled closer, worried. "What's wrong?"

"I thought de Haan was behind me…" he muttered. Then he looked her in the eye and she knew that he now believed, at least enough to be afraid for his missing shipmate, because de Haan was definitely not with the group. He spoke up, his tone urgent. "Sir, we've lost de Haan."

Vishinsky was whirling around in anger at the interruption before the words registered, and by then the Doctor was already running.

"We'd better find her then, quickly! Stay together," he yelled over his shoulder, moving fast enough that no one had a hope of staying with him.

Sarah caught at Harry's hand as they rushed after him, determined to keep at least one of her friends close by, and noticed that the strange chill and the weird atmosphere began to dissipate the moment they left the clearing, apparently localised around the probe.

Something was there, all right, and it definitely knew something was up.

Shouting for de Haan, they crashed through the undergrowth, which was beginning to glow luminescent again as afternoon became evening – a bad sign, surely, the night was dangerous, Sorenson had said – and then between one step and the next the temperature dipped once more and Sarah stumbled, still clutching at Harry's hand, into a small clearing.

De Haan was there, still standing, just, her body rigid, wide open eyes glazed over, staring at nothing. She was ashen, almost grey, lips tinged blue, skin beginning to wrinkle and shrivel…they were too late, _too late_, Sarah desperately thought, and there was a _presence_ there, she could feel it, a disturbance in the air that was invisible and yet she knew it was aware of them…and then, with a crackle, it was gone.

The air became warm once more. De Haan collapsed.

Harry rushed over to her, swiftly joined by the Doctor and Vishinsky, and suddenly everyone was there, all babbling in agitation.

Sarah hung back, knowing she couldn't help. "Is she dead?"

"Not quite," said the Doctor, pulling back to allow the others room to work.

"Can she be saved?" Vishinsky's urgent demand was directed at Harry, the designated medical officer, who floundered, casting frantic eyes toward the Doctor as if expecting – perhaps hoping for – him to take responsibility for the emergency, with his greater knowledge and expertise…but the Doctor seemed content to leave it to him.

He did that quite often, Sarah had noticed. If someone else possibly _could_, he'd step back and leave them to it, not interfere. He liked people to help themselves. And it freed him to focus on other priorities – like trying to save everyone else.

Harry's hesitation lasted only a moment before he collected himself, took a deep breath and just got on with it. "Well, I don't know, but we can certainly try. She needs fluids, a blood transfusion – your med bay…?"

Vishinsky's determination to re-arrest them had vanished without trace.

"You'll find everything you need. Go." Casting a sharp glance around at his team, he selected one at random, rapped out, "Utoblo, go with him, assist," and turned back to Harry, who was already lifting de Haan's body from the ground. "The plasma infusion unit is built into the bio-beds, Utoblo can show you."

Harry nodded and hurried off without a backward glance, as fast as he could go with de Haan's dead weight in his arms, Utoblo scurrying after him. Sarah stared after them, remembering Carly de Haan's friendly smile and willingness to believe, when no one else did. Was there any way she could be saved? Harry had admitted ignorance of the probe's medical technology and what did he know, really, about reversing whatever this creature had done?

He was willing to try, though. That mattered.

"All right, Doctor. I'm off the fence." Vishinsky looked haggard, as if all the stuffing had been knocked out of him. "Explain your theory – what do we do?"

"How long until launch?" the Doctor sombrely asked.

"Not long. Sorenson was anxious to be gone before full night and we must achieve lift-off before the power drain cripples us – the fuel reserves were already low."

"But we have a little time, yes?" It was the Doctor's turn to hesitate, just for a moment, his keen mind whirring away behind those brilliantly blue eyes, weighing up options. "Captain Salamar isn't open to reason, and neither is the professor, so perhaps our only hope is to approach the other side, appeal to them before it's too late. But how to communicate…?" He whirled around. "Sarah, the place Sorenson showed you, where the crystals were found – do you remember the way?"

Sarah hesitated, tried to orient herself. She wanted to say yes, but it had been so dark and Sorenson's route so haphazard, his pace so frantic, she knew she'd struggle to find the place again. "I'm not sure – I can try…"

"I know the way." Vishinsky's eyes were deeply troubled, but he'd committed himself now. He turned to his two remaining underlings. "This is unauthorised action – you should return to the ship."

"We were assigned to you, Commander," said Landa, chin held high, eyes glittering with determination, but still as cool and collected as ever. "You may still need us."

Wijyaya rolled his eyes a little, but nodded.

"Well, if she's going I'm going," he drawled, patting at his head self-consciously, as if he feared a hair might be out of place. "I'd hate to miss out on all the fun."

His tone was insouciant but there was a hint of steel behind it. Vishinsky eyed him sternly, then narrowed his eyes at Landa, who folded her hands behind her back and met his gaze unblinkingly. Wijaya lifted an eyebrow, a stubborn, nonchalant gesture of _what are you going to do?_ Vishinsky sighed.

"Rank insubordination," he chided, but there was no rancour in his voice. Nodding tiredly, he turned back to the Doctor. "Very well. This way."

dwdwdwdw

Charging back to the probe with a fast-fading life in his hands – literally – Harry hadn't stopped to think about what he'd do when he got there, being an escaped prisoner and all.

He did think about it, too late, when he reached the glade, moving from humid air to chilly between one step and the next, only for the ever-dour Ponti to pop out of the probe like a jack-in-the-box and train a gun on him.

"That's far enough. Where are the others?"

There was simply no time for explanations.

"This is an emergency, we must get to the medical bay," Harry urgently insisted, ably backed up by young Utoblo, who was all but bouncing with agitation at his side.

"Medical emergency, Ponti – let us through!"

"What's wrong with her? What did you do?"

It was all so absurd and the situation so urgent, Harry could no longer summon the energy to be indignant at being accused yet again.

"She was attacked, just like the others, but there's still a chance she can be saved if you let us pass!"

Ponti glared at Utoblo. "But the prisoner…"

"Go tell the captain then, but let us through, she's dying!" Utoblo shrilly squawked.

Torn between conflicting priorities, the man growled in exasperation, but at last stood aside to let them board the probe.

"On your head, Utoblo – the captain's already on the warpath. Stay with him!"

Harry remembered the route this time and rushed on to sick bay, mind a-whirl with the effort of translating what he believed the patient needed into what he'd learned of this technology, painfully aware of how little he knew.

Utoblo hurried after him, moaning, "Shouldn't have shouted at him, he ranks me, I'm for it…"

Carefully placing de Haan down on the nearest bio-bed, Harry tried to remember where the controls were – and what did what. They'd analysed corpses earlier; a live patient was an entirely different proposition, and the patient's condition was far too urgent for any mistakes to be made.

"Are you familiar with this equipment?" he demanded.

"A little – why?"

More by luck than judgement, Harry found the 'on' switch and was heartened when the bed lit up to show that it was functional, the scanner which had earlier displayed test results for the dead now detailing the flickering life signs of his patient. She'd lasted this long. There was still a chance.

"I don't entirely know my way around this equipment," he admitted. "So I need assistance – and I'm afraid you're it…Nurse Utoblo."

Utoblo's eyes went wide with alarm at the responsibility being placed on his young shoulders. He glanced across the room toward the mortuary cabinets where the three corpses were now stored, looked down at de Haan and swallowed hard, but then nodded determinedly and looked Harry squarely in the eyes.

"All right, then. For Carly. What do you need me to do?"

dwdwdwdw

"The transference is unstable," the Doctor explained – or at least, Sarah presumed he thought he was explaining, although she wasn't much the wiser, hurrying after him at full pelt as he charged through the forest. "The victims are always alone, had you noticed – but you said you were with Sorenson, Sarah?"

He stopped so suddenly she almost ran into the back of him, blazing eyes suddenly fixed on her, an anomaly in the pattern he'd spotted. Except that…

"No," she realised, casting her mind back. "No, he'd gone on ahead when it happened. And then it stopped when he came back."

Those brilliant blue eyes gleamed with something like triumph, mingled with affection; she'd confirmed his theory. He started moving again, talking rapidly still.

"Just as de Haan was released when we found her. Harry and I had gone on ahead the first time you were attacked. De Haan was alone when she was attacked. Bartrum was alone. Everyone who died was alone. The victims have been picked off individually, opportunistic, and if someone else arrives on the scene they're released – an unstable transference, broken by the introduction of a variable."

"Then what are we worried about?" demanded Vishinsky, panting with exertion.

"The power drain, Commander. They've learned how to draw power – from the base, from the probe. The logs confirm the base only lost power at the very end, which means this is new, that power intended for a purpose – and they were massing around the probe. Which way now?"

"This way." Recognising at last where they were, Sarah took the lead, scrambling up the steep incline that led to the plateau.

Again she was struck by the chill of that rocky hillside, and this time knew enough to connect it with the invisible creatures, recognising also a hint of that strange, thrumming tension in the air – not as noticeable as back near the probe, but she could feel it nonetheless. Evening was drawing in fast, but it was still light enough here, away from the shade of the trees, to see that Sorenson's jumble of equipment was gone now, removed to the probe for the journey home. The crystals were still there, though, twinkling in the dusky half-light.

"Ahhhh." The Doctor bent to scoop up a handful, his expressive face lit up with fascination. After all this time, everything they'd been through, this was his first glimpse of them. "I wonder," he murmured, turning to Vishinsky without completing that thought to ask, "How many did you take?"

"Two crates, no more," Vishinsky defensively replied. "As you can see, we've barely dented the volume available – surely no one would even notice –"

"Oh, but they have, Commander. They've noticed, all right. Don't you see? Can't you feel it?" As the Doctor dropped a few crystals into Vishinsky's unresisting hand, Sarah remembered the tingling sensation she'd felt when she handled them, like a mild static charge.

But Vishinsky only shrugged. "The crystals have unusual properties, it's true – that was the purpose of Professor Sorenson's research, he says. He's found a means of harnessing their potential as a fuel source."

"Pah. Is that all you see? Potential? Power? Profit? Take two crates of these with you now and then what? Return with a whole fleet for the rest? Humans!" The Doctor's voice dripped with derision. "Deplete your own resources and go searching for more to exploit, is that it?"

Vishinsky's expression became closed off and angry, his tone defensive. "The Morestran Federation is in desperate need of –"

"Feel that?" The Doctor reached out to close the man's hand tight around the crystals. "Feel the energy? Yours for the taking, is it? You fools. Blind, greedy fools."

"Then what's the solution?" Vishinsky shouted. "What would you have us do?"

The Doctor spun around, stepping to the edge of the crater at the centre of the plateau.

"Look down there," he said in a light, conversational tone, as if the anger and disdain of a moment ago had never happened. "What do you see?"

Sarah glanced down at the inky black surface, a foot or so below the edge.

"It's a pool," she said with a shrug, wondering where this particular tangent might be leading.

The Doctor lifted an eyebrow, flashing an aggravatingly knowing smile. "Look again. Wouldn't you expect to see a reflection?"

She looked, and saw what he meant. There was no reflection. The surface of the water – or whatever it was, not water; something else – was completely dull and matt and still. It wasn't even a something, more like a…a _nothing_, a void where a something should be.

"That isn't water," exclaimed Landa, kneeling for a closer look. She found a pebble and dropped it in – but instead of landing with a splash, it was absorbed without as much as a ripple. "What is it?"

"I shouldn't get too close, if I were you," the Doctor warned, and she pulled back, turning puzzled, curious eyes toward him.

"Why? What is it?" Sarah sharply asked. She knew that voice, it was the voice he used when he thought he was onto something and began to make plans accordingly, always several steps ahead of everyone else and never thinking to communicate properly.

He was as infuriating as he was captivating.

"This is the nexus," he said. "The point of intersection between our universe and the other."

Sarah stared at it, a gaping abyss of nothingness, just lying there among the rocks.

"And the crystals?" She looked at them again, piled up around the edges of the crater, shimmering softly.

"They can only be found here, at the nexus, nowhere else." His expression rapt and thoughtful, the Doctor bent to take up another handful, let them trickle between his fingers. "Feel that energy. They exist in a half-state, right on the cusp between dimensions. Fascinating!"

"But what _are_ they?" Wijaya spoke up for the first time. His dark brown eyes were troubled and even his coiffed, colourful hair looked subdued.

"That," said the Doctor. "I should very much like to find out."

"You said something about communicating with these creatures," Vishinsky reminded him, shrewd eyes narrowed to regard him closely.

"I did," the Doctor agreed, staring intently down into the crater.

Sarah's skin was prickling, goose-bumps rising on her arms. He had a plan, she knew, and she wasn't going to like it. "Doctor, what are you up to?"

The Doctor clapped his hands together and rubbed them briskly.

"Well, we must communicate with these creatures, Sarah," he boomed in that careless, confident way of his. "Unless we talk to them, find out what they want, how can we resolve this situation? It's entirely possible they don't even know how their touch affects human bodies. Here, take these."

Pulling a crumpled paper bag out of his pocket, he emptied sticky jelly babies out of it into her hand and then tipped a few crystals into the bag in their place, twisting the neck of the bag to secure it before dropping it back into his pocket.

"Insulation," he explained with a careless shrug, taking a step back, his brilliant blue eyes fixed on her face, solemn and searching. "Alone," he said. "I must go alone."

A chill ran down Sarah's spine. The jelly babies tumbled from her hand. "Go where? Doctor…"

"Oh, Sarah Jane." He smiled gently, reaching out to lightly touch her arm. "I'll take care. Wait here."

"Wait, what are you doing?" Vishinsky demanded.

"Oh, I'm not entirely without influence," the Doctor airily assured him, stepping right up to the edge of the crater. "And contact must be made, there's no other way. Here goes nothing – I hope I'm right!" His tone was absurdly cheerful as he stepped forward again, forward and down, into the crater, into that gaping nothingness.

He vanished completely.

dwdwdwdw

With Utoblo's help, Harry managed to get de Haan hooked up to the plasma infusion unit Vishinsky had talked about, marvelling once more at such splendid medical technology. He discovered how to adjust the nutrient content to suit her specific needs – even how to determine those exact needs with remarkable ease and precision that he rather wished he could take home with him, always assuming he ever made it home again – had Utoblo search the computer for the Morestran equivalent of the medication he thought she should have, and found a warming blanket to drape over her, to raise her core temperature.

Without much more he could usefully do, for the time being, he was anxiously monitoring her condition for any sign of improvement when a commotion at the door heralded the arrival of Captain Salamar, in bullish mood.

Utoblo had been fluttering around like a butterfly, anxious and upset and full of earnest helpfulness, but he came to a quivering halt now, struck dumb by the disapproving presence of his captain.

"What have you done to de Haan?" Salamar demanded, eyes flashing and pallid cheeks flushed pink.

Harry was tired of such accusations now, so decided to ignore this one.

"I'm treating her for severe dehydration and hypothermia, Captain," he said with as much professional good cheer as he could muster. "We've started a plasma infusion, although ideally a blood transfusion would –"

"That's not what I meant and you know it," Salamar interrupted. "How did you escape?"

"Well, the door wasn't actually locked," Harry mildly replied, opting not to add that the Doctor had picked the lock of their restraints.

Salamar glared at him.

"Commander Vishinsky and two other members of my crew were last seen chasing your accomplices into the forest. They have not returned and we can't raise them on comms." He glanced up as the lights flickered, snapped a curt, "Find out what that is," to Utoblo, and turned back to Harry to demand, "Where are they?"

The question brought Harry up short as he suddenly realised he had absolutely no idea where the Doctor and the others might have gone, if they'd not followed him back to the probe.

"Well, I suppose the Doctor would want to investigate further," he slowly suggested.

Salamar exploded. "Investigate what, exactly? Phantoms? Ghosts? Why should I believe in an unseen killer when I have flesh and blood stood before me, with no good reason for being on this planet? Admit that you killed these people –"

"Why?" Harry angrily burst out. "Why on Earth would I bring this girl back here for treatment if I were the one who'd attacked her in the first place?"

"Sir, they didn't do it." Utoblo spoke up now, hand poised over the communication panel on the wall. Eyes wide at his own daring, he looked younger than ever, but his voice was steady and determined. "All three of them were with us when de Haan was attacked. And we saw the thing that did it, sir – that is," he became flustered, "We _didn't_ see it…but we saw something. It wasn't them."

A muscle worked in Salamar's jaw. He had no idea quite what to think or do, Harry realised, but was desperate to assert his authority anyway – and that was never a good combination.

"Look, we really are on the same side here, Captain Salamar, I assure you," Harry offered, wondering what it would take to convince the man.

Salamar opened his mouth to reply…and an alarm went off.

dwdwdwdw

Sarah cupped her hands around her mouth and bellowed into the void that was the nexus, "DOC-TOR!"

The minutes were ticking by fast, full night drawing in faster still, the chill in the air intensifying rapidly, and there was still no reply, still no trace of the Doctor. The Morestrans' communicators weren't working, so they couldn't make contact with their ship, and Vishinsky was beginning to look at Sarah with an almost unbearably sympathetic expression.

"I'm sorry," he said, with no-doubt kindly meant pity. "But I don't think he's coming back."

"Of course he's coming back," Sarah sharply retorted.

"If his theory is correct," said Vishinsky, "Then he's stepped into the vortex between dimensions – ceased to exist. How could anyone come back from that?"

_Ceased to exist_. Sarah felt cold, deep in the pit of her stomach, in a way that had nothing to do with the temperature on this hillside. She couldn't – wouldn't – believe it.

"The Doctor knows what he's doing," she stubbornly insisted. She might never have studied cosmology, might know nothing of the science involved, but she knew the Doctor, trusted him absolutely. "You heard him: he had a plan to communicate with the aliens." But looking down again at the nothingness that was the nexus, certainty warred with fear for her friend because the Doctor's plan had been no more than theory and she knew it, and her voice became very small. "I just wish he'd hurry up."

More than that, she wished there were something – anything – she could do to help.

"It's getting very dark, sir," Landa quietly piped up. She was shivering, rubbing her arms in an attempt to warm herself.

"We can all see that," drawled Wijaya, his sardonic humour back in place, but Sarah could see the cracks in it now, the anxiety it was attempting to mask.

Landa turned on him, her composure suddenly giving way to a flash of anger. "We were supposed to take off before full night, Eslam, they're waiting for us – this mission was unauthorised…"

"It was your idea to come, trotting after your hero commander –"

"Enough," snapped Vishinsky, and they subsided, glaring at one another. "Technician Landa is right: we can't wait any longer. We'll return to the probe –"

"No, we can't!" Sarah protested in alarm. "We can't leave the Doctor!"

"The Doctor is gone," Vishinsky firmly declared. "It isn't safe for us to stay here – the important thing now is to return to the probe and leave this world before any more lives can be lost."

"And then what?" Sarah furiously argued. "Will you have the captain leave his cargo behind? Will he listen to you? The Doctor said you couldn't take off with it on board."

"Why?" demanded the commander. "What's to stop us? I can't act without good reason."

Sarah almost laughed. "After everything you've seen, you don't think you have good reason?"

Vishinsky looked tired.

"For that," he said, "No. Sorenson won't abandon his discovery, not now, and Salamar –" He broke off before he could say anything that might malign his captain, turned away and began pacing fretfully.

"Look out, something's up," Wijaya suddenly called out.

Sarah turned just in time to see the inky void of the nexus stir, disturbed for the very first time. A hazy shape became visible through the gloomy half-light, and began to ascend from the void – it was the Doctor…but Sarah's relief lasted only an instant.

He seemed to hang in the air, hovering over the void as if suspended on an invisible string like a puppet. His eyes were wide open, staring sightlessly ahead, his skin waxy pale and his body rigid: a frozen statue, almost ghost-like, completely stripped of all his usual energy and animation.

Was he even still alive?

"No!" Sarah breathed, staring at him in horror.


	5. Chapter 5

**Part Five**

The alarm was followed by an urgent call over ship-board communications: captain to main exit, emergency. Salamar lost interest in Harry at once, snapping a curt, "Stay with him," at Utoblo before sprinting away.

Harry stared after him, torn, then cast frantic eyes toward his comatose patient. She shouldn't be left untended, and yet…

And yet he couldn't just stand here, simply had to find out what was going on out there – it could be the Doctor and Sarah, perhaps they were in trouble, even injured…

He was running almost before he knew the decision had been made, young Utoblo hot on his heels squawking, "Wait – no – you're not supposed to," and sprinted through the featureless hallways that led back to the probe's main entrance, where consternation appeared to be reigning.

Pushing through the clustered crewmembers, Harry saw the cause of the disturbance and murmured a dismayed, "Oh, I say."

Harlow Ponti was dead, just inside the entranceway, his body dried-up and wizened in the same way as all the others. There was a chill in the air and a sort of thrumming sensation that reverberated through the teeth, just like outside in the clearing – but if it could be felt here, if Ponti had been killed here, inside the ship, then surely that meant…

"What have you done?" Salamar turned on him, white with rage.

"Me?" Harry's jaw dropped. What kind of magician did the man think he was, to kill someone from the other side of the ship?

"But he was all right when we came aboard, I spoke to him," said Utoblo, wide-eyed and upset, but very definite about what he knew. "I told you, sir, we saw a thing – an invisible thing! It attacked de Haan – and B-Bartrum…" his voice hitched and trailed off, but he received no sympathy from his captain.

"You accused the female stranger earlier." Although Salamar addressed Utoblo, his cold blue eyes remained fixed on Harry, who was too exasperated to be alarmed.

Utoblo swallowed hard but stood his ground. "I was wrong, sir. I hadn't seen it then. I've seen it now – I saw what happened to de Haan. It wasn't the strangers; it was something else, like they've been saying. I never saw anything like it –"

"And with such vast experience you would surely know," Salamar sarcastically snapped.

The lad flushed.

"Sir, I know what I saw," he stoically insisted.

Salamar unexpectedly relented, just a little.

"And I also spoke to Ponti, after you accompanied Sullivan aboard – but the other strangers remain unaccounted for, along with three members of my crew, so I want an armed guard on _this_ one," he jabbed a finger in Harry's direction, "And –"

A sudden jolt sent everyone reeling, accompanied by a noticeable drop in temperature. The lights flickered again, before dying completely, and a crewman shouted for them all to look.

At the door, the air seemed to be shimmering, flickering in electric reds and blues, as if _something_ intangible were out there – trying to get in.

"Crikey!" Harry stared at it, clutching at a stanchion to steady himself. He'd seen and felt nothing at all when Sarah was attacked that first time, had been aware of intense cold and a crackling sound when they found de Haan, but this… "It's getting stronger," he realised, astounded.

Salamar and his men, meanwhile, reacted in time-honoured military fashion, whipping out their guns and firing, with absolutely no effect, all the while yelling at one another, orders and such, until someone finally managed to hit the button that would close the door – an effort that cost the man his life, as he was dragged out of the ship by an unseen force even as the door closed.

The lights and temperature returned to normal, for one blessed moment of absolute silence and stillness in which everyone seemed to be holding their breath, just waiting to see what would happen next.

It wasn't over. The lights began to flicker again. There was another jolt – and another, as if something were buffeting the sides of the ship trying to get inside, again and again, the assembled crewmembers lurching and reeling.

Harry hung onto that stanchion to maintain his footing, and, looking at Salamar's frozen expression of shock and bewilderment, couldn't quite resist a sour jibe of, "Well, Captain – do you believe me now?"

dwdwdwdw

The Doctor's mouth opened, and a voice that wasn't his rang out, echoing unnaturally. "You seek communication."

Sarah didn't have even a second to react, as three guns were instantly trained on him. Too furious and frightened for caution, she whirled around to block them, reaching out to catch at the weapons and thrust them down and aside.

"No, don't you dare! Don't you dare!"

Only when she was sure the Morestrans weren't going to shoot the Doctor out of hand did she turn back to him – or whatever was speaking through him.

"What have you done to the Doctor?" Her heart was pounding and there was a tremor in her voice. She'd seen what these creatures could do to a body, had felt the chill of their touch. And now they had the Doctor.

His mouth opened again, but the lips did not move to frame the repeated words, "You seek communication."

Was it just repetition – or was it also an answer to the question? Sarah tried to understand.

"Yes," she warily replied. "Yes, we seek communication with the…the beings who live here. That's why the Doctor went into the pool – he wanted to talk to you." She remembered what the Doctor had said, that they might not even know the effect of their touch, and asked again, "What have you done to him?"

"We have no form on this plane," was the reply, spoken through the Doctor but not by him, his mouth opening and closing in a grotesque parody of speech without ever even coming close to actually shaping the words spoken. "This one gives us voice."

"Do you mean the Doctor agreed to this, agreed to be your mouthpiece?" Would he do that, when it removed him from the negotiation he'd wanted? Had he understood what would happen? Had there simply been no other way?

"We seek communication," said the alien voice through the Doctor's mouth. Sarah could hardly bring herself to look at him, those staring, sightless eyes with no trace of the keen mind that should lie behind them. The Doctor couldn't negotiate like this, a puppet for the aliens to speak through, so it was up to the rest of them, he was relying on them. She tried to think. What did they need to know? What could they say that would resolve this?

Vishinsky pushed forward to stand at her side, gun in hand still.

"You've been killing our people," he shouted.

"Intruders come, take, despoil," was the reply. "We feel them come, awakening to danger. They see us not. We cannot talk."

"The survey team," Sarah murmured, realising for the first time that their arrival must have felt like an invasion. How many times had she helped fight off alien attacks on Earth? These creatures had just as much right to defend their world, surely, and yet…she remembered the suffocating chill of their touch and shivered.

Vishinsky was in no mood for either diplomacy or understanding, his tone bitter and accusatory. "You couldn't talk to them, so you killed them?"

The response was vehement. "We feel them, see them, taking. It is not theirs! We seek communication, reach out – touch the aliens."

"When you touch us, we die," said Sarah, remembering again what the Doctor had said. Was it possible they didn't realise? "Did you know that?"

There was a slight hesitation before the reply came, slowly and carefully enunciated, like someone struggling to find the right words in an unfamiliar language.

"So far to reach, the divide must be bridged. We try, we reach – contact! So strange – so warm, so moist. We must know more. We draw strength. Send the emissary." The voice became stronger, fiercer, its passion strangely juxtaposed with the impassive blank of the Doctor's face. "The aliens take, destroy. We draw strength. Reach. Act. The aliens will be stopped."

Sarah struggled to make sense of this garbled speech.

"But they didn't know," she desperately argued. "They didn't know they were stealing – they didn't know you were here."

"They will not heed. Disturbance at the place of beginnings. The aliens take," that intense voice continued. "Ravage and destroy. Beginnings will end. This cannot be allowed. The aliens must be stopped. Already we act."

"Already?" Sarah didn't like the sound of that.

Alongside her, Vishinsky sounded horrified. "The probe – what have you done to the probe?"

dwdwdwdw

The probe shook again, more violently than ever, and this time Harry really did lose his footing, sent sprawling across the cold mesh flooring with Salamar and Utoblo in a heap on top of him, other crewmen strewn all around.

Salamar was frantic and furious. Clawing his way upright, he staggered toward a wall-mounted communication unit and bellowed urgent orders into it.

"Red alert, red alert, we are under attack – operate forcefield barrier, full power! All crew report to assembly point immediately and prepare for immediate take-off –"

"Wait – no, you can't!" Appalled, Harry scrambled to his feet and lurched toward him, clutching at the walls for support as the probe shook again. "Sarah and the Doctor are out there – your own people!"

"They are gone!" Salamar's face was white and drawn, eyes wide, pupils blown. Shock, Harry rather distantly diagnosed: the chap really hadn't believed. "You saw that thing. Anyone still out there is gone. I must protect my command."

"Now wait just a minute, Captain Salamar." As Salamar charged off down the corridor, bellowing orders, Harry hurried after him. "You can't abandon them!"

"They are already dead!"

"You don't know that." Harry wasn't about to believe the worst until he had good reason; they'd all been fine when he left them. The ship lurched again and the lights were still flickering, he had absolutely no idea how they could possibly hope to stave off this attack, still less make it past the alien creature in search of the others, but he was certain that, "The Doctor's the best chance of survival any of us have got."

"I disagree," snapped Salamar, charging around a corner and through a high, wide doorway onto the upper deck of a spacious split-level room, stuffed full of control panels and screens, all fully manned and positively buzzing with activity. It was the bridge – the command centre of the vessel.

As Salamar swiftly strode across the deck, a tall young woman, olive-skinned with a thick braid of dark hair reaching almost to her waist, hurried to meet him with a status update. Harry strained to make sense of the technical jargon. Power levels were low, that much was plain, and the forcefield barrier was only partially repelling the alien attack, weakening rapidly.

"Activate cyclostimulators, Morelli," Salamar brusquely ordered. "Power jets to lock in positions."

The woman, Morelli, swiftly carried out these commands, hands moving across a control panel with practiced ease. "Activated and locked, Captain."

The ship shook again, a view-screen showing the shimmering red-blue form of the alien outside – or aliens, perhaps. It looked like a swarm, buffeting and bouncing against the forcefield barrier.

"Activate gyrostabilisers and prepare for final ignition," Salamar ordered.

Morelli's hands moved across the panel again. "Activated. Launch in ten, nine…"

"Captain Salamar, please," Harry desperately pleaded. "You can't just abandon them."

Morelli reacted with surprise, her head turning sharply to flick worried side eyes at the captain – she hadn't known that members of the crew were still outside…but her inexorable countdown continued: "…seven, six…"

"The mission is complete. I must protect my ship, my crew," Salamar stubbornly insisted.

"You're leaving members of your crew out there to die!" Harry shouted, frantic with fear for Sarah and the Doctor. They couldn't even retreat to the safety of the TARDIS because it was here, on board the probe – once it took off, they'd be completely stranded, at the mercy of the alien creatures.

"…four, three…"

The lights faded and an alarm abruptly began to sound, the ship shuddering and juddering in a way that was completely different to the shaking and buffeting of the alien attack.

"Pressurisation failing, Captain," Morelli called out, her close-set eyes wide with alarm, startlingly blue against her dusky complexion. "Cyclostimulators are not responding."

"Activate secondary launch units," Salamar bellowed. "Get us away from that thing!"

On the view-screen, the shimmering form of the alien swarm was no longer bouncing off the forcefield barrier but wrapped around it, as if squeezing it tight, a blazing glow of energy, growing brighter by the second.

"Incredible," breathed a new voice. "It's energy – pure energy in physical form!"

Harry turned to see Sorenson standing in the doorway staring at the screen in rapt fascination, bloodshot eyes rimmed with unhealthy shadows, his dishevelled appearance a stark contrast to Salamar's spick-and-span crew.

The ship was bucking wildly now, engines groaning, crew panicking.

"I don't understand," shouted Morelli.

"Increase power," Salamar ordered.

"The Doctor warned you, Captain Salamar," Harry remembered. "He said you wouldn't be allowed to leave with those crystals on board."

Sorenson caught at his shoulder angrily, a curious glint in his eyes.

"The crystals are essential. It was the whole purpose of my mission – a new fuel source, light and power for billions."

"We could do with some of that now! Emergency power units inoperative," Morelli called out. "Main and secondary units are failing."

"Captain, we must make it back, my mission depends on it," Sorenson fervently insisted, as if his mission were all that mattered, as if there weren't countless lives at stake here.

"Divert power from other systems," Salamar ordered.

"It's not working," Morelli shouted, and the ship was now rattling so violently it seemed almost on the verge of shaking apart completely.

"We must break free!" Salamar insisted. "We must."

"The engines can't take it, Captain," Morelli frantically reported. "They'll blow!"

Salamar stared out at the brilliant red-blue glow of the alien, holding the ship in place however wildly it bucked and shook.

"It doesn't make sense," he snarled through gritted teeth, the ship jerking and juddering, its engines shrieking. "All right!" he shouted at last. "Cancel ignition!"

dwdwdwdw

"You have to give us time," Sarah pleaded, but the alien speaking through the Doctor seemed utterly implacable.

"Time is past. The aliens are ours." There was real venom in the voice now.

"But we've spoken to you now – we can explain to the others, make them understand."

"Don't be so sure," Vishinsky muttered under his breath. Sarah shot exasperated side eyes at him.

"We'll make them understand," she firmly repeated, hearing desperation in her own voice. They simply had no defence. The aliens had been drawing power for a purpose, the Doctor had said – if that purpose was to attack the probe, maybe even destroy the probe…Harry was on board – and the TARDIS.

Salamar's entire crew, come to that.

"If the crystals are left behind," she offered. "Will you allow us to leave safely? If we promise not to take anything, not to come back, will you let us go?"

Silence. The Doctor's rigid body hung over the nexus, sightless eyes staring past her shoulder at nothing.

Then, "Where do they go? Other worlds, alien worlds, so many worlds. They came to us, now we must act," the voice spoke through him, leaden tones like a death knell, and Sarah didn't know what more she could do, what more she could say to convince.

"We're sorry." Landa suddenly pushed past Vishinsky to stand at her side, shoulder to shoulder, back straight, chin held high, voice low-pitched and clear. "We're sorry that we came. We're sorry that we took from you. We ask you to allow us to make it right."

"Please," Sarah added. "Let the Doctor go. Leave the ship alone – we'll make sure your crystals are returned. We promise."

"You'll never get them back if you destroy the ship," Wijaya drawled over her shoulder.

She waited as the alien fell silent again, her heart pounding so fiercely she was sure everyone else must be able to hear it.

At last the response came. "The aliens will be released. Return what is ours and we –"

The voice cut off abruptly as a brilliant beam of light fell across it. Wijaya had turned on a flashlight to counter the growing dark of night.

In the same instant, the Doctor sagged, fell – Sarah dived forward to catch at him before he sank back into the nexus, knowing she couldn't hold him, and was grateful for the reflexes of Vishinsky and Landa who reacted likewise, their combined strength sufficient to bear his weight and haul him back to the relative safety of solid ground, unconscious and deathly pale.

Was he breathing? Sarah couldn't tell.

"Quickly," snapped Vishinsky, hauling the Doctor's limp body into his arms. "Take his legs, Wijaya. Back to the probe, double-time!"

dwdwdwdw

"Why?" Captain Salamar demanded, rounding on Harry with flashing eyes and bright pink spots in the middle of his pallid cheeks. "Why can't we take the crystals? What does that thing want?"

"Well, I don't rightly know," Harry admitted, wishing the Doctor were here to explain himself. "But it's what the Doctor said."

"And if the Doctor said it, it must be true," Salamar scoffed. Well, he could mock all he liked, but he didn't know the Doctor.

"Yes," said Harry with as much dignity as he could muster, ignoring Professor Sorenson's disgruntled mutterings behind him. "Captain Salamar, I've known the Doctor for quite some time now, long enough to know that he knows what he's about, even when he sounds completely potty…well, especially when he sounds completely potty, in fact. His theory was –"

"His theory is unimportant," Sorenson interrupted, his voice breathless and intense, staring meaningfully at the captain. "Remember what we spoke of, Salamar, the importance of my mission."

Whatever they'd spoken of, Salamar was clearly in no mood for it now. "Your assurances mean nothing, Professor, if your mineral samples are jeopardising the safety of my command –"

"The whole purpose of your command was to get me and my work back to the Federation," Sorenson indignantly protested, but Salamar shook his head.

"We were diverted to find out what happened to your team, Professor, nothing more. Not if it endangers my ship."

There was something rather brittle, almost menacing about Sorenson's single-minded focus. Thwarted, he turned fiercely on Harry, who was rather taken aback by the manic glint in his eye.

"Who is this man? What does he know?" he demanded, flecks of spittle flying from his mouth. "I am the expert here and my mission takes precedence, you agreed that, Salamar."

"The situation has changed," Salamar snapped, angrily jabbing a finger at the view-screen on which the alien form shone livid, maintaining its iron grip on the probe. "I'm well aware of your position, Professor, but I am in command of this probe and my decision will be final. If we can take your cargo we will, but I will not risk my ship."

"Then you'd best get shot of those crystals, pronto – the Doctor was certain they're at the root of all this," Harry repeated, suddenly hopeful that Salamar might be swaying to the right way of thinking at last. If he'd only agree to jettison the cargo, perhaps the aliens might leave them alone and they could get a search team out for the others.

Sorenson twisted his hands in distress. "If you abandon that material, you destroy everything I've worked for – the future of our civilisation!"

"Captain, look!" Morelli suddenly broke in, pointing at the view-screen. "It's gone – that thing's gone!"

Harry stared at the screen in surprise. Just a moment ago that blazing energy creature had been out there, lighting up the night sky, yet now there was no sign of it, the ship suddenly still, no longer so much as a quiver to indicate resistance of any kind.

Why? Why had it stopped now?

"Then we're free," Salamar said in a breathy, disbelieving voice.

"More to the point," Harry enthused, deciding that explanations could be the Doctor's department, once they found him – first things first. "We can get out there now and start looking for the others."

Salamar stared at him and for an all-too brief moment he dared to hope that the man would agree – that common sense and basic decency might prevail.

But panic was flickering in the captain's eyes and he shook his head.

"Can't take the risk," he muttered under his breath, and turned back to Morelli, suddenly all business once more. "Morelli, activate compression units and prepare for immediate take-off."

It was Harry's turn to stare, speechless with disbelief.

"No!" he managed to vocalise at last, the alarm that had only just subsided flooding back in full measure. "Captain, our people are still out there, we can go after them now, bring them to safety –"

"It is regrettable," Salamar insisted in tones that brooked no refusal, but he avoided Harry's eyes as he said it. "But I maintain that anyone still out there must surely be dead already –"

"You don't know that!"

"…and I cannot risk this ship or any more members of its crew on a wild goose chase. We must get away while we can. Activate cyclostimulators."

"You'd just leave them?" Harry couldn't believe it.

"And my cargo, my work?" Sorenson eagerly enquired.

Salamar's expression was set like stone.

"Your mission was commissioned at the highest level of Federal Government, Professor," he conceded, and Sorenson preened like the cat that had the cream. "With the alien gone, it takes absolute precedence –"

"Poppycock!" Harry had never in his life spoken to a ranking officer in this manner – but then again, he'd also never been so disgusted and furious with anyone in this position.

"Power jets locked in position, Captain," said Morelli, her expression worried and her tone uncertain. "Ready to activate gyrostabilisers – unless…"

"Unless what?" Salamar snarled. "Would you wait while our enemy regroups for another attack? Send more of your shipmates out to their deaths? No, I cannot risk further delays, the manual says –"

"And what does your judgement say?" Harry demanded. "How can you possibly justify abandoning innocent people – your own crew?"

Salamar glared at him, absolutely unyielding, still with that flicker of panic behind his cold blue eyes.

"Activate gyrostabilisers, Morelli," he ordered, rather feebly adding, "Another ship will be sent to search for survivors, one better equipped to respond to the alien menace."

"Gyrostabilisers activated. Ignition in ten, nine…" Morelli began the countdown, a slight wobble to her voice.

"Well how long will that take?" Harry protested, scanning the control panels around him in despair. Even if he could get near, he'd never find the right buttons to stop the launch now – blow the whole ship up, more like. "Do you really believe they can last that long out there? They need our help _now_, Captain, while we have the chance."

"…seven, six…"

Salamar huffed a little and still wouldn't meet his eyes.

"Anwar, send out an occuloid to monitor the planet, transmission on maximum beam. Any data gathered will be of use to the return mission, and if there are survivors it will locate them for retrieval – will that satisfy you, Sullivan?" he querulously demanded. "This world _will_ be conquered, you mark my words."

Harry did mark his words, and was not the slightest bit reassured, glumly certain both that no one out there could possibly survive until another mission was sent and that all these colonial ambitions of the Morestrans would only end in further disaster.

What could he do to stop it?

"Can't leave with the crystals aboard, you said," Sorenson gloated.

"…two, one – lift off!"

dwdwdwdw

"What's that sound?" Sarah asked, alarmed at the sudden roar ringing through the forest, knowing deep down what it was but not wanting to believe it.

From the shocked looks on their faces, her little band of allies didn't want to believe it either.

"The probe's taking off." Landa looked and sounded stunned. "Commander, they're leaving us!"

That was it. That was what Sarah had suspected, what she hadn't wanted to believe. The probe couldn't leave without them, it couldn't…

"Keep moving," Vishinsky growled, adjusting his grip on the unconscious Doctor.

They kept moving, reaching the edge of the glade in time to feel the residual heat of the launch, the probe itself already high in the sky and ascending fast, gleaming brightly in the starlight.

"They've gone, they left us," Wijaya dumbly, redundantly said, while Landa tremulously asked, "Commander? What do we do now?" and Sarah simply stared, feeling as if someone had punched her in the stomach, knocking the breath clean out of her lungs. The Doctor was unconscious, injured, he needed medical help which was even now moving further and further beyond them – and with the TARDIS on the probe, out of reach, they were completely stranded here, no way of escape, and…

"But we promised," she recalled, an ice-cold trickle of dread running down her spine. "We told them we'd return the crystals – they trusted us…"

The four of them stared at one another, and Sarah realised she was holding her breath, just waiting for the other shoe to drop.

"Is it just me," drawled Wijaya with a very deliberate and determined attempt at his old cynical nonchalance, "Or is it starting to get cold?"

"Into the base, quickly," Vishinsky promptly ordered.

As Sarah ran ahead to hold the door for Vishinsky and Wijaya, hampered as they were by the Doctor's dead-weight, she felt again that by now familiar freezing sensation, heard the dread crackle in the air.

"They're here!" she managed to shout, throat constricting, limbs seizing…too late, too late, she couldn't escape, breath freezing in her lungs…and then suddenly, in a blinding blaze of light, she was free again, gasping but free; the cold and the crackling were still there, all around, but that dreadful grip on her had gone.

The beam from Landa's flashlight had fallen across her. And the aliens had let her go.

"Get inside, now!" snapped Vishinsky, coming up behind her with the others. "Seal the door, Landa!"

As the men carefully set the Doctor down on the floor, Sarah dropped to her knees to press her ear to his chest, the way she'd seen Harry do it, first one side and then the other. It was the first chance she'd had – they'd come so far, delayed so long, it may be too late…but no. No. She could hear his hearts beating, both of them. He was breathing steadily.

A shuddering sigh escaped. She raised a shaking hand to push windswept hair out of her face, pressed it to her mouth and tried to compose herself.

"Will it hold them?" Wijaya was asking.

"I doubt it," the commander grimly admitted. "But what else can we do? There's nowhere else to go."

Sarah sat back on her haunches. It was bitterly cold even inside the building and she could still hear that crackling sound.

"They're all around us," she realised, fearful. "And they know we broke our promise – they're angry…"

"_We_ didn't break any promise," Vishinsky snapped. "We just didn't get here in time."

"Same difference," Wijaya pointed out, quickly adding, without sounding the slightest bit apologetic, "With all due respect, of course, Commander."

But the aliens weren't actually attacking – and Sarah thought she knew why.

"The lights," she said. There was no power for the main lights in here, but they had three flashlights between them – would that be enough? "Sorenson said that daytime was safe, they come at night. They let go of the Doctor when the light came on. They don't like light – do we have more?"

"Search the cupboards," Vishinsky immediately ordered.

The search turned up four lamps, small but bright, which made seven lights in total, enough to make a small and very ineffective-looking ring for five people to shelter within, holding the crackling alien presence at bay.

"They'll never last the night," Landa dully pointed out. "Not if the creatures can drain power from batteries."

"They have to last," Vishinsky dourly replied. "They're the only defence we've got."

Sarah knelt at the Doctor's side and took his hand. If only he'd wake up – he'd know what to do, surely, some brilliant scheme to pacify the aliens and call the probe back…but he just lay there, pale and still.

It was freezing in here. Perhaps there was still a measure of safety in numbers but the aliens were all around them, she knew, poised to attack.

"We're on our own," she despondently murmured, wondering how long they could possibly hope to last.


	6. Chapter 6

**Part Six**

"I say – they're there! Captain, I see them!" Harry shouted, eyes fixed on the tiny screen bearing the feed from the whatchamacallit – the occuloid, whatever that was – which had been launched just as the probe took off. It was far too high to make out much detail, but tiny stick figure images of Vishinsky and his party could clearly be seen, rushing across the glade toward the base. His heart leapt with relief when he saw that Sarah was still with them – and the Doctor, too…but he was being carried by the others, something was wrong…

"Turn that feed off!" Salamar snapped. "Record but don't display. Set course for Morestra."

The words sank in only slowly, the order unthinkable, incomprehensible. It had been bad enough that he presumed them dead without evidence – but this?

"You mean you aren't going back?" Harry stared at the man in dismayed incredulity. "Knowing they're there, alive – Captain, we _have_ to go back."

"I don't _have_ to do anything," Salamar furiously retorted. "_I_ am in command here. I will not risk this ship and I will not tolerate any further dissent. If I weren't in need of a replacement medic I could have you spaced for sedition, Lieutenant Sullivan. As it is, you will consider yourself under my command until we reach Morestra, when your future will be decided. Guards, secure this man in the medical bay. Attend to your patient, doctor."

dwdwdwdw

"But why?" Sarah bleakly wondered, sitting alongside the Doctor's prostrate figure hugging her knees to her chest. "I don't understand why – why would they just take off like that when they knew you were still out here – why didn't they wait?"

Vishinsky sighed.

"Captain Salamar," he wearily replied, stressing the title in a way that made it sound almost like a curse, "Is both ambitious and inexperienced…and the good professor has turned his head with promise of wealth and glory."

"But to abandon his own crew…"

"_Great_ wealth and glory." Vishinsky's voice was tinged with bitterness. "Sorenson is not wrong, as it goes – the mineral resources of the Federation are waning, new supplies urgently needed. The man who provides them will be a hero. So will the man who saved him."

"Would you have done it?" she challenged, and he sighed again, shaking his head.

"Never leave a man behind," muttered Wijaya, looking depressed. Even that silly little goatee beard of his looked crestfallen, as if the bottom had dropped right out of his world. "That's what they taught us, that was the training."

"Then why would the rest of the crew go along with it?"

"Captain's orders," Vishinsky softly replied. "Mutiny is punishable by death. Half the crew are straight from basic, green as they come. This was intended as a shakedown cruise," and there was that bitter note again, "A charting mission – soft and simple for Salamar's first command. Pah," he snorted in derision. "So much for that!"

They fell into glum silence, the icy air around their inadequate light circle crackling with quiet menace. It was only a matter of time – the lights would fail, or the aliens would work out how to get past them, or something.

"There's something I still don't understand." Landa unexpectedly spoke up, head tilted to regard Sarah quizzically from beneath her deep fringe, like a puzzle she was unable to make out. "We were sent here, a rescue mission, but you…your friends were questioned earlier, but they didn't give a straight answer. What _are_ you people doing all the way out here?"

Sarah wondered what exactly the Doctor and Harry had said. Not that it mattered, the truth was the truth.

"I don't suppose there is a straight answer to give," she admitted, shrugging tiredly. Now that she'd actually stopped, sat down to rest, her body was making known just how long it had been on the go, adrenaline leeching sourly away leaving enervation in its wake. "We don't really have a reason for being here. The Doctor was supposed to be taking us back to base – to Harry's base, that is. I'd have gone on home from there…until next time."

That had been the pattern for so long she no longer questioned it. She went off on these jaunts with the Doctor for however long they lasted, and then they went back and the Doctor carried on with UNIT and she got on with her life, wrote a few articles, paid a few bills, went on the odd date, maybe helped save the world if it happened to need saving while they were home, and then they went off on another trip again…

Except it wasn't really like that any more, was it? Not since the Doctor had changed, turned from the man he had been, the man she'd first known, into the man he was today. Between one thing and another, they'd barely set foot back on Earth since it happened, and even that had been in answer to a direct summons, a call for help, stopping long enough to save the day only and then taking off again immediately – she hadn't even made it back to her flat to check the mail. He still talked about going back, made all kinds of promises, but he also found any excuse he could to go anywhere else but Earth, one diversion after another, and she hadn't questioned it because she was enjoying the ride wherever it may lead, the thrill of exploration and adventure, unlike anything she'd ever experienced before – or ever would again.

"Well, that was the plan, anyway," she murmured, wondering just how accidental this particular detour had really been. "But the Doctor never has liked to take the direct route anywhere."

"That's what the others said." Landa was clearly not convinced, frowning as she attempted to puzzle through the problem logically. "But this quadrant is at the far end of the known universe, to journey here from Earth would require a mission of not just months but years – this isn't a detour to anywhere. It sounds so unlikely, that's why your story couldn't be believed, why so much time was lost."

There was an accusatory note to her voice now, but Sarah was too tired and too worried to care.

"Well it's true," she said, and whatever anyone might have said in response was forestalled because the Doctor chose that moment to stir, the tiniest of movements but enough to draw her whole attention, exhaustion forgotten. "Doctor? Doctor, can you hear me? It's Sarah. Doctor?"

The Doctor groaned, eyelashes fluttering, and finally opened his eyes, focusing on her with some difficulty.

"Oh, Sarah, it's you," he said with a feeble smile.

"Lie still," she hastily urged as he began to push upright, but of course he didn't pay the blindest bit of attention, stubbornly making it to an almost upright position, although not without help. He groaned and moaned and shook his head, grimacing and grinding the heel of his hands into his temples, and finally looked around with some surprise to see where he was.

"Well," he said at last, rather weakly. "That was a lot less enjoyable than I'd hoped!"

dwdwdwdw

"At least you seem to be hanging in there, old thing," Harry glumly told the comatose figure of Carly de Haan, whose condition was definitely stabilising, although she remained unconscious. Her skin tone had improved markedly, temperature approaching normal – he was almost confident now that she would recover. It was some consolation, at least, considering what a mess everything else was.

He'd been mad to set foot inside the TARDIS again, he bitterly reproached himself. Should have known better – a fat lot of use he'd been.

To rub salt in the wound, Sorenson's blasted cargo was right here, in the medical bay, sharing the quarantine field with the TARDIS. Harry stared disconsolately at the crates, locked away behind that shimmering barrier. They were the key to all this, he was sure – but what could he do with that key?

Getting the forcefield shut down would be a start, although he had no clear idea of what could be done beyond that.

To keep busy, as much as anything else, he set about the control panel he thought might be responsible for the forcefield, in search of anything that might be an 'off' switch, only for a commotion to start up at the door almost at once.

Harry hurriedly jumped back from the controls and endeavoured – badly, he knew – to act nonchalant as the door slid open. Young Utoblo stepped into the room carrying a tray, casting a mutinous glare back at the guard on duty just outside.

"Even prisoners have to eat," he groused over his shoulder as the door slid shut behind him, and to Harry he added, rather more brightly, "I've brought you some food."

Harry hadn't eaten since the TARDIS landed on this benighted planet, which had to be a good 24 hours ago now; he'd also be exhausted, he knew, if he weren't so worked up.

"Thank you," he said with absolute sincerity, hungrily tucking in.

Utoblo glanced furtively over his shoulder at the door.

"Also," he began, lowering his voice, but then dried up, biting at his lip and staring down at his boots.

Harry stopped eating. "Something the matter, Ensign?"

"_Sub_-ensign," Utoblo corrected. He clearly wanted to say something more, but couldn't quite spit it out, finally turning away with an exasperated sigh and crossing the room to stand at de Haan's bedside. "How's Carly?"

"On the mend, I believe," Harry was happy to report. "I should think she might wake up fairly soon."

"Really? That's good news, at least!" Utoblo's worried face lit up – but then fell again. He picked at a fingernail. "Do you think," he faltered. "Do you think we could have saved Leo, if I'd got to him in time?"

Now there was a question.

"I think," Harry carefully replied, "That we can't possibly know. We were very lucky with de Haan."

"Of course." Utoblo nodded and looked away, biting at his lip. "It's just," he began in a very small voice. "He was…I mean we…that is. Shipboard…_fraternisation_…it isn't allowed, you know. But he was…and I thought maybe…and now." He hung his head. "Well, it doesn't matter now, does it? That wasn't what I wanted to say."

Rather relieved that he wasn't going to be called upon to dispense anything in the line of emotional reassurance, which he really didn't feel up to, Harry said, "What's troubling you, Sub-ensign?"

Utoblo kept his back turned, shoulders hunched and posture defensive, breathing hard and visibly wrestling with himself. At last he spun around, his worries bursting out.

"Commander Vishinsky and the others – the captain left them behind!"

Harry let out a sigh of relief to finally hear someone else voicing similar concerns to his own.

"I was beginning to think no one else on the ship cared about that," he admitted.

"Everyone cares," Utoblo indignantly insisted. "But the captain gave his orders, so that's final – nothing to be done."

"I think there's plenty could be done," Harry countered. "If we leave them down there, they'll die."

"But the captain said –"

"Do you think he's right?"

Utoblo studied his boots once more. "It doesn't matter what I think," he muttered. "The captain's given his orders."

Harry sighed again.

"My orders were to see the Doctor safely back to base," he gloomily said, turning to look at the TARDIS again – sitting right there, but inaccessible and inoperable without the Doctor. "I'm afraid I haven't done a very good job."

"You saved Carly's life!"

"But I couldn't save my friends."

Utoblo's brow furrowed. "I heard the occuloid spotted them. So we know they aren't dead."

"Not yet, but they will be if we don't go back for them," Harry was sure.

Utoblo moaned and clutched at his head. "I don't know what you want me to do. There's nothing I can do!"

dwdwdwdw

"They call themselves Natara," said the Doctor, already beginning to sound more like himself, although he looked, in Sarah's opinion, like death warmed over. "A kind of collective consciousness, if you will – each mind unique and distinct, yet interlinked. Fascinating…I wonder if I might have a drink of water."

The request was tacked onto the end of the statement so casually that Sarah almost missed it. It was Vishinsky, sitting on the floor alongside her, who glumly answered, "It's outside the circle."

"Circle?" Eyebrows shooting up into the mess of unruly curls flopping across his forehead, the Doctor peered quizzically at the feeble little ring of light all around them. "Oh, I see. That's rather ingenious – it won't hold them out indefinitely, of course."

"Of course," Sarah sighed, because what else had she expected? "That would be too much to hope for."

"They're adapting," the Doctor warned. "They don't really understand our organic sort of life, you know, they've never encountered it before, barely knew this dimension existed before the survey team came poking around – but they're learning fast, picking up new tricks."

"Comforting," Wijaya wryly remarked.

"Yes, isn't it," the Doctor grimly agreed. "To them, our dimension is as intangible as they seem to us, which limits their ability to interact, but we can't rely on that. They were fumbling around blind at first, lashing out, before they stumbled upon the power supply and realised they could draw on it to stabilise the manifestation – give themselves a bit of oomph, as it were."

"You seem to know a lot about them," Vishinsky suspiciously observed.

"Well, my mind was temporarily joined to their collective, after all," the Doctor pointed out. "And I do have some experience in these matters – their thought patterns aren't easy to decipher, but I learned more from them than they learned from me. Enough to know that we must tread carefully, the agreement you struck was a good start, but…" He peered around again, his expressive face crumpling with confusion. "It _was_ a good start, so why exactly are we holed up in here, hiding in the light?"

"Ah," said Vishinsky, his craggy face set in doleful lines, heavily shadowed in the uneven light, which gave him rather a ghoulish look.

"The probe's gone," Sarah flatly explained, no sense beating around the bush, but she found that she couldn't quite meet the Doctor's eyes as she explained, "Took off and left us – before we even got back here, never mind had a chance to return the crystals. So we haven't kept our promise."

How high a price might they pay for that failure? Her stomach churned sourly as the Doctor said, "Oh," and then, "Oh dear," and, "Well, that is a good reason to hide away here in the light, I will give you that," and although his tone was light, his face was sombre, and the air in the room seemed chillier than ever all of a sudden. Or was she just imagining it?

"I seem to recall you mentioning," said Vishinsky, "That that they'd never allow the probe to take off with the crystals aboard."

The Doctor gave him a hard look. "They released the probe because a promise of cooperation had been made, a promise which has not been kept – the ship may have taken off, but it hasn't escaped yet. And we're still here. But that isn't the worst of it."

Something about the tone of his voice and the deadly serious glint in his eye made Sarah shiver in a way that had nothing to do with the chill in the air.

"You do think we're still in danger, then," she said, and she'd already known that, had known it since the moment she saw the probe take off with the crystals still on board, and yet somehow, somewhere deep inside her had been a stupid, desperate hope that she might be wrong, that the Doctor would wake up and know better – but there was nothing reassuring about the look on his face just now.

"More than ever," he said. "And not just us. If the crystals had been returned, that might have been an end to it, perhaps, but they're out there now and that changes everything."

"Why?" Landa asked, shaking her head in disbelief. "You keep talking, but you never explain. What's so important about two crates of stones?"

"You might well ask that question of Professor Sorenson," the Doctor sternly told her. "They were important enough to him that he allowed his team to be picked off one by one, rather than abandon the mission early by calling for help. To him they represent wealth and glory – and for your captain, too, it seems. He abandoned you for the sake of getting those crystals safely back to Morestra – and in doing so he may well have damned your entire civilisation."

Sarah blinked in surprise at this dramatic statement, and saw Vishinsky's jaw drop open and Landa's brow furrow, while Wijaya, looking mystified, said what they were all no doubt thinking: "Er…what?"

The Doctor sighed. "It's really rather difficult to explain. There was a clue in something Harry said earlier…" He stopped, glancing around again with a slight frown. "Where is Harry, by the way?"

Sarah looked upwards, toward the ceiling above her and the sky beyond that and the probe somewhere above it again, way up among the stars by now.

"Gone," she glumly replied. "Him and the TARDIS both. He went back to the probe, remember. He'd have been on board when it took off."

The Doctor lifted an eyebrow. "Well, that's something, I suppose," he mused.

"I don't see how," Sarah grumped.

"Do you remember what he told us about the results of the bio-scan? The touch of the Natara leaves trace elements of an unusual mineral residue."

"We couldn't identify it," said Vishinsky, while Sarah wondered for the first time if she also had that mineral residue somewhere inside her – she'd been touched by the Natara as well, if only for a matter of seconds.

"Because it is absolutely unique to Zeta Minor," said the Doctor. "And would it surprise you to learn that the mineral residue in the bodies of the Natara's victims has the same chemical composition and atomic structure as the crystals we found at the nexus?"

"So they're related!" Sarah realised, wondering what that meant.

"More than related. That's what I learned when I joined with the Natara consciousness," said the Doctor. "They're spores."

dwdwdwdw

"Look, if you could just see your way to letting me out of this room, perhaps I might try talking to the captain again – persuade him to turn the ship around." It was a lousy plan and Harry knew it, and young Utoblo stared at him in disbelief.

"That – would – be – _mutiny_!" he hissed through gritted teeth. "They'll throw me out the air lock – and you, and all!"

"Well, we must do something," Harry insisted. He couldn't think quite what, but the alternative was _un_thinkable.

"But we can't. I can't," Utoblo moaned. "He's the captain – he knows what he's doing. He must know what he's doing."

"I'm not so sure, old chap." Harry remembered the look on Salamar's face as the alien attacked, the panic in his eyes as he gave the order to flee rather than wait to retrieve his missing crewmembers.

"You're an officer," Utoblo miserably protested. "Not one of ours, but still an officer. What if it was your captain? Would you be so quick to go against orders then?"

The face of Brigadier Lethbridge-Stewart flashed before Harry's eyes, stolid and unflappable, steady as a rock. He thought of Commodore Bennetts up at Faslane Naval Base and Captain Arnold on the Ark Royal, good men one and all. Would any of them have made the same call as Captain Salamar…and what might he have done if they had? Orders were orders, after all. It was rather a sobering thought.

"I rather hope I never have to find out," he admitted with a heavy heart. "I'm sorry, old chap, I know you have your orders, I shouldn't ask…but I simply can't leave my friends down there to die."

Utoblo pouted at his boots.

"They might be all right," he hopefully offered. "You don't know…"

"I do know," Harry began to insist, breaking off with a start as the door slid open. This visitor was even more unexpected. "Professor Sorenson!"

The professor didn't reply to the greeting, didn't as much as glance sideways. He hadn't seemed entirely well before, but looked downright ghastly now, wincing and squinting, flinching away from the lights, his waxy face beaded with sweat. As the door slid shut behind him – open only long enough for Harry to see that the dratted guard was still out there, barring any escape – he operated a switch to turn off the main lights and then moved to stand at the edge of the quarantine bay as if drawn by a magnet, staring down at the crates containing his precious cargo with an odd, almost hungry glint in his eye.

dwdwdwdw

Sarah eyed the Doctor uneasily. "Okay, when you say 'spores', you mean…?"

"I mean spores – infant Natara, dormant, left to mature in the unique environment of the nexus, feeding on the natural energies there, the place where two dimensions touch. The 'place of beginnings' they call it, part of their lifecycle – and they knew it only as a breeding ground until the survey team came poking their noses in. But now they know. Now they know there's a whole universe out here."

He leapt to his feet suddenly, swept up one of the lamps and dashed over to the computer console, pulling open a lower panel to begin rooting around inside.

That brought everyone to their feet in alarm.

"What are you doing?"

"Well, now we're for it."

"You've broken the circle!"

"Oh, we seem to be all right for the moment – they've shot their bolt, over-reached themselves, need a while to regroup and recharge. That gives us a little time," the Doctor's voice floated back from somewhere within the guts of the computer.

"A little time to do what?" asked Sarah impatiently, attempting to peer over his bulky shoulder in hopes of some clue as to what he thought he was doing. He never explained properly.

The Doctor resurfaced, bushy curls standing on end, hands full of wires and circuits, eyes full of manic, almost gleeful energy. He was recovering, back to himself, and the sight of it filled her with hope.

"Time to prepare a defence, of course," he said, darting around the room collecting seemingly random bits of equipment as he went. "Come on, what do we know about these creatures?"

"They're invisible and they kill," Vishinsky flatly replied, sitting back down looking depressed.

The Doctor was clearly hoping for slightly more positive input and shot a reproving look at him. "Yes, and?"

Sarah remembered the near misses she'd experienced and what had happened to de Haan, wondering anew if Harry had been able to do anything for her.

"They can be deflected," she said. "If you get there in time.

"Good, and?"

Landa piped up with, "They're light-averse."

"To a degree, yes. And?"

"From another dimension," Wijaya sardonically drawled. "Just visiting in ours."

"They can drain power from our systems," Landa added.

Sarah tried to think. There had to be more. What else had they learned? "Um…they're a hive mind…"

"A collective consciousness," the Doctor corrected. "That's not quite the same thing. Yes, and we've also learned something quite important overall: that while the Natara may have certain advantages over us, they also have certain weaknesses, which we can use."

He'd assembled quite a collection of equipment by now, dropped it onto a clear work surface alongside the computer console and began to sift through the mess, discarding some and focusing on others.

"Can we use it to kill them?" Vishinsky was interested now, clambering back to his feet to watch. The Doctor shot a baleful glower in his direction.

"Not if we can help it," he firmly said, opening the lamp to extract its battery, leaving the room just that bit dimmer; Sarah picked up a flashlight and took it over so he could see what he was doing and he caught her eye, just for a second, by way of thanks. "This is their world, we're the intruders here – the Natara are simply protecting their young. Or were. Wouldn't you do the same? No." He frowned down at the assortment of equipment, shaking his head. "No, this isn't quite right, there's something missing – I don't suppose there's a frequency modulator around here somewhere, Samina – perhaps in the gravimetric scanner?"

As Landa scurried to look, he continued to talk, his deft fingers working away all the while, taking things apart and constructing something new.

"We are the aggressors here," he repeated, frowning down at his work. "But we must defend ourselves, at least until the situation can be resolved. The Natara are able to cross into this dimension – that's part of their natural lifecycle, after all – but full manifestation requires power, which they've been drawing from the solar cell here at this base. It's what they used to attack the probe, a tremendous concerted effort – and it very nearly worked, but they spent their load on it, so to speak. Come dawn, the solar cell will begin to recharge and they'll draw on it once more to re-fuel for another push, but if we can isolate the wavelength they use to make the transfer…"

"How can we do that?" Landa had found the device he'd asked for and pushed alongside him to watch with great interest as he opened it up and removed part of the mechanism, which he then began to build it into the contraption he was assembling.

He grinned, reached into a pocket and pulled out a bulging paper bag, tipping purloined Nataran crystals – spores – into her hand.

"With these. I took them as insulation when I went into the nexus, but they'll also help us here – thrifty, no?" He carefully slotted one of the crystals into his contraption, wiring it in place before connecting the lamp battery. "Find the right frequency and we can build a buffer to hold them off: power for us but not for them."

He glanced up at Sarah with that stupidly infectious grin of his, and she grinned back, heartened by his confidence. "So what then? And what about the probe – and the stolen crystals?"

"Oh, one problem at a time, please, Sarah," he cheerfully reproved. "Who knows? Perhaps by morning Harry will have persuaded Captain Salamar to turn the ship around."

"He didn't stop it taking off," Sarah muttered, but that was unfair and she knew it and was annoyed with herself, quietly adding, "They've probably got him locked up somewhere."

"More than likely," Vishinsky agreed. "Salamar is a proud man, highly conscious of his position. He won't tolerate dissent – and the lieutenant _is_ likely to dissent, is he not?"

"More than likely," the Doctor rather absently echoed his own phrase back at him, head bent over his work. Vishinsky eyed him curiously.

"Doctor, you seem very certain that the spores taken aboard the probe are a threat. If they are dormant, as you claim, where's the danger?"

The Doctor turned wide blue eyes upon him. "They _were_ dormant. Removed from the stabilising forces around the nexus, what do you think might happen?"

Sarah was alarmed by the implication. "Will they hatch? Like eggs?"

"Spores don't hatch." The correction came from Landa. "They germinate."

"Germinate, then," Sarah impatiently said, catching Wijaya's eye as he winked his amusement at his shipmate's pedantry. "Will they germinate?"

"The Natara thought it probable," the Doctor distractedly agreed, fussing over his experiment. "It's why they massed to attack the probe when they knew it was leaving, I felt their alarm, when I was joined to the collective mind – and something else…"

"But surely whatever infants are spawned could be no danger to anyone," Vishinsky optimistically argued. The Doctor gave him a hard look.

"Do you really believe that? No, Commander. They won't be infants in the human sense. They will be Natara – propagated prematurely, perhaps, separated from their home and kind, but that will only make them more dangerous. They'll be born into the wrong universe, confused, angry – and with a powerful survival instinct. They'll need to feed – and they'll have the race memory of the collective consciousness to spur them on. Think what the Natara have learned since the survey team came here. They've learned that our universe exists, beyond the tiny gateway that's served as their breeding ground. They've learned they can function here, in one form or another, that there is fuel and food for them – the electrical energies used in our technology and the warmth and moisture of human bodies, so easily drained by their touch. They've learned that we exist, and are hostile to them – their territory has been invaded, their dormant young attacked and abducted. What more excuse do they need? We came here, Commander, brought ourselves to their attention, and we took them out there, showed them the universe. What else should they do but set their sights on it? And there's something else…"

Elastic face contorting with frustration, he rapped his knuckles against the side of his head.

"Think, think! Something at the back of my mind, something I've overlooked – something I learned from my time with the collective – some contingency set in place…because in one sense you are right, Commander, the newly born Natara _will_ be immature, but they still pose a threat, I felt that. The Natara knew the probe was leaving, taking the spores, it was why they attacked, but they knew they might not succeed, they were prepared…"

"Emissary!" Landa suddenly exclaimed. "Back at the pool, the nexus, when the Natara were talking – they said they'd sent an emissary."

The Doctor stared at her, mouth open. Then he slapped a hand to the side of his face.

"That's it. Of course! That's how they knew, how they learned so much so fast – but how…unless…no, surely not! But would he even be aware…?" Talking rapidly to himself, he pulled a face. "Possibly not – almost certainly not – and yet…no. No, it must be. There's no other explanation…"

"No other explanation for what, Doctor?" Vishinsky impatiently demanded.

"Think about it, Commander. Who experienced the greatest exposure to the Natara? Who worked at the nexus daily? Who survived when the entire survey team were slaughtered?"

"Professor Sorenson." The cold Sarah felt now had nothing to do with any Natara present in the room. "What are you saying, Doctor? What do you mean?"

The Doctor's expression was grim. "I believe, Sarah, that the unfortunate professor has a passenger."

dwdwdwdw

"Er…is everything quite all right, Professor?" Harry cautiously asked, unnerved by Sorenson's odd behaviour.

It was hard to see clearly, the room lit only by the greenish glow of the monitors and screens, but the man didn't seem to recognise that anyone else was in the room at all, stood staring intently at the crates of crystals, the flickering, shimmering forcefield casting deep shadows across his sickly pale face.

Utoblo took a hesitant step forward. "Professor?"

Sorenson showed no sign of having heard. Moving slowly and deliberately, more like an automaton than a man, he stepped over to the control panel Harry had observed earlier and pressed a few buttons.

The forcefield vanished.

dwdwdwdw

"That's it!" the Doctor shouted, interrupting himself mid-sentence. He thrust his improvised gadget aside and rushed back to the computer console.

Sarah followed with the flashlight, certain that he couldn't actually see in the dark, however excited he was about whatever he was doing. "What's what now?"

"The frequency," he said, working feverishly at the circuits deep within the console. "I've isolated the precise wavelength of the Natara's intra-dimensional transference – we can use it to build a protective circuit, a buffer, prevent them draining the solar cells when they recharge. Help me with these connections, Samina."

Sarah quickly stepped aside to allow Landa to pass, and felt warm breath huffing against her ear as Wijaya moved closer, peering curiously over her shoulder. Alongside him Vishinsky fidgeted fretfully.

"Doctor, what you were saying about Sorenson," he worriedly said. "You really think the probe could be in danger?"

"I'm certain of it," said the Doctor, eyes fixed on his work. He scowled. "This is no good. I don't suppose there's a laser micrometer around here somewhere?"

"Saw one in the crew quarters – I'll get it." Wijaya darted away.

The Doctor issued a complicated technical instruction to Landa, which seemed to make sense to her although Sarah didn't understand a word of it, and then said, "I should have realised earlier. It all makes sense now. No wonder the man was in such a state – sharing your mind with a passenger, whether knowingly or not…it's enough to unhinge anyone."

"Passenger," Vishinsky wonderingly murmured. "You used that word before."

Did he really not understand? Or did he simply not want to understand. The Doctor's meaning seemed clear enough now to Sarah.

"You're talking about possession," she said. "You think the Natara have possessed him somehow."

"In a manner of speaking. It explains so much: a Nataran consciousness lodged inside his mind, the reason his life was spared – an unwitting spy, as it were. Almost a suicide mission for the Natara in question once the probe lifted off: no way back. And now especially…"

"He'll need to be there when the spores germinate," Sarah realised.

"Exactly," said the Doctor, eyes fixed on his work. "And while the Natara may have been a mere passenger at first, observing and reporting back to the collective, we now know that they can assume full control of a host body – _they_ now know that they can assume full control of a host body. His first priority will be to ensure the safety and survival of the newly born Natara as they propagate…Commander, whereabouts on the ship was the cargo stored? In the hold?"

All eyes turned to Vishinsky, who paled.

"No," he said. "We placed it in the quarantine field in the medical bay."

dwdwdwdw

Harry watched uneasily as Sorenson knelt beside the crates and began to pull at the catches to open them.

"Er…I'm really not sure you ought to be doing that, Professor."

It was no good, Sorenson wasn't listening.

The lid came off the first crate, and for the very first time Harry caught a glimpse of those ruddy crystals that were at the heart of all this.

He hadn't seen them before so he couldn't be sure – were they supposed to be glowing like that?

dwdwdwdw

"So instead of being secured in the hold, where it might at least take them some time to find their way out, the spores will germinate at the very heart of the ship, surrounded by people – surrounded by _bodies_!" the Doctor shouted in dismay. "Warm, moist human bodies to feed on – or to latch onto as hosts, like parasites."

"Harry's on the ship." Sarah's voice wobbled, because Harry was a doctor and he'd gone back there with a patient – if she wasn't dead and he wasn't in a prison cell, they'd both be in the medical bay. With the crystals.

"My crew is on that ship," said Vishinsky, grim-faced.

"And the ship is heading for Morestra," said the Doctor, bending over his work once more, his deft fingers flying. "We'll make contact at first light, as soon as the solar cell regains enough charge to power the transmitter. If I can just finish this…where's that laser micrometer?"

"Wijaya went to…get…it." Sarah stuttered and slowed mid-sentence, because he'd been gone far too long and she hadn't realised – hadn't stopped to think.

"It shouldn't take this long, it was just on the –" Landa broke off, eyes widening in alarm.

The door through to the bunk room had closed behind him, and it was quiet out there, too quiet. In all the bustle and rush, they'd grown careless, forgotten the danger.

"He went alone," said Vishinsky, grim-faced.

Sarah reached the door first, Vishinsky and the Doctor at her heel. She threw the door open and then skidded to a halt, because it was too late – _too late, again_ – and how could they have let this happen?

Landa pushed in alongside her, gasping, "Eslam?"

He'd slumped against one of the bunks, his handsome, bronze-toned face wizened and grey, the coiffed, colourful hair he'd been so proud of dried up like old straw, and he'd known, they'd all known, they'd all known the danger, how could they have been so stupid…

His eyes opened, and Sarah leapt back with a yelp that was pure shock.


	7. Chapter 7

**Part Seven**

"Oh, we thought you were dead!" Sarah gasped as Wijaya slowly, awkwardly began to struggle to his feet, instinct urging her to rush over and help…but even as the words escaped she knew her relief was unfounded, and the Doctor's hand dropped onto her shoulder to hold her back.

"Don't get too close," he gently said.

Because Wijaya was dead, he had to be…and yet he was standing, his movements jerky and uncoordinated, his sightless eyes wide open and staring. A puppet.

Sarah felt sick. How had they let this happen?

"Natara," Vishinsky growled through gritted teeth. "What have you done? Leave him alone!"

"He'd done you no harm; there was no need to kill him." The Doctor's voice was filled with sorrow.

"Aliens are not to be trusted." It was the voice of the Natara that spoke, using Wijaya's body as a mouthpiece.

Pressed alongside Sarah, Landa was quivering, while at her heel she could almost feel the waves of fury coming off Vishinsky.

"_You_ are not to be trusted! Let him go," the commander barked.

"What do you want?" The Doctor pushed forward to stand at the front of the group. "You've killed many times before without taking possession of the body afterward…or…no, is that it? An experiment, to find out what's possible, is that what you're playing at?"

The Natara was moving Wijaya's body again, as if fascinated by the way it worked – rotating joints and flexing digits, tilting the head and blinking the eyes.

"We had not realised," said the alien voice, and its stolen lips were no longer quite as out of sync as they had been, the facial movements becoming more natural.

But that was worse, Sarah decided: worse than the unnatural puppetry of just moments ago, because Wijaya's body was so wizened and shrivelled that the most natural of movements looked all the more wrong, a gruesome reminder that this was still a corpse, animated only by the alien consciousness lodged within it.

"We had not realised," said the Natara. "We had thought the aliens fit only for sustenance, variation to our diet and fitting reward to their intrusion. We had not realised they could be more."

"More? More?" snapped the Doctor. "No, wait, don't tell me. Let me guess. Sorenson proved you could lodge within a human body without destroying it, so you used him to spy on his people for you and he never even knew it. Then I went into the nexus and you learned you could take full control of a living body – and you'd need that, wouldn't you, for any serious campaign on this plane of existence, your ability to interact is otherwise strictly limited. You realised that if you could take full control of me, you can also take full control of Sorenson, use him to protect the spores, now they're out there, and when they germinate, he'll be there to guide them. A whole ship full of hosts, borrowed tangibility…but there's a snag, because the young will also need sustenance and you've got the taste now, haven't you, the taste for humans. Heat and moisture, salt and iron, but there won't be enough to go round, not if they're still needed to fly the ship. So you experiment, here, while you've got the chance, because if you can both feed and still make use of the body afterward, well – the universe is your oyster, isn't it, now you know it's out there. Today Salamar's space probe, tomorrow Morestra, the whole galaxy by a week on Thursday, with Sundays off for good behaviour – am I right? Parasites – you'll spread like a plague!"

Wijaya's eyes narrowed, head tilting to one side to listen. The Natara inside him hissed.

"It was not our choice to leave this place, alien. Now it is done, what will be shall unfold. The young must flourish."

"Must flourish, eh? Well, it's a good excuse, I suppose, shame it doesn't wash. Stolen bodies won't last indefinitely, you know. Oh come on, it doesn't have to be like this – just how close are they to germination?" The Doctor was edging sideways now, reaching toward a counter nearby – trying to get at that tool he'd wanted. "There's still time. We can bring them back, no harm done –"

The Natara got there first, Wijaya's body moving startlingly fast, for a corpse, his fingers closing clumsily around the tool and holding it aloft in triumph.

"You wish for this, needed, to use against us – we felt it in the mind of this alien while it still held thought. No, you shall not have it. The time for negotiation is past. The time for making peace is past. It is done. You will not deny us. We shall rejuvenate and destroy all intruders. The young will go forth and flourish. They will bring back more vessels, so that more shall go forth. Aliens will be –"

A beam of light fell across Wijaya's body and the voice cut out, his wizened corpse collapsing unceremoniously to the floor. Sarah spun around to see Landa holding up the largest, most powerful lamp available, her face set like stone.

"That's enough!" she snapped. "You will leave him alone now."

"Good timing, Samina. I don't believe they had anything more useful to add." The Doctor strode forward to bend over Wijaya's body, hesitated slightly and then patted his shoulder, an awkward yet strangely affecting gesture. Then he took the laser micrometer from Wijaya's hand and turned, grim and resolute. "Stay together as a group or in pairs at all times, they'll pick off any stragglers. Quickly now – that buffer must be in place before dawn."

"And the probe?" asked Vishinsky anxiously.

"It's vital that we make contact as soon as possible," said the Doctor. "Anyone in the vicinity of those spores when they germinate could be infected."

dwdwdwdw

"They didn't look like that before," exclaimed Utoblo, staring at the glowing, pulsing crystals in rapt fascination, and an alarm bell went off in Harry's head.

"They didn't?" He wasn't sure what that meant, but was certain it couldn't be anything good.

"Soon," Sorenson crooned. It was the first thing he'd said since entering the room and he didn't sound like himself at all. "It's almost time, almost time!"

The crystals were getting brighter, palpitating visibly in a way that no stone really ever should. The Doctor always said that one should trust one's gut. Harry took Utoblo's arm and steered him toward the door.

"I think we should leave," he said, because he might not know what was going on, exactly, but experience suggested that, whatever it was, hanging around to watch would not be the wisest choice.

"But you can't – the captain said – and the professor…" Utoblo spluttered, gazing back at Sorenson in concern and wringing his hands, but he operated the door control obediently enough and there they hit a snag.

"Where d'you think you're going?"

"Ah. Officer." Harry had forgotten about the guard on the door.

"We need to see the captain – there's something wrong with Professor Sorenson," Utoblo urgently babbled.

The guard was not impressed. "He's in the right place, then, isn't he? What are you doing in there anyway, Utoblo? Don't you have duties to be getting on with?"

"He does. I need him here." Sorenson had come up behind them, sickly pale and sweating. His voice still sounded wrong, almost as if it were someone else's voice entirely.

"Well, there you go. Sorry, kid," said the guard with a grin, hitting a control to close the door. Harry caught at it and tried to hold it open.

"Wait. Can't you see something's very wrong with this man?"

"There'll be something wrong with you if you don't get back." The guard prised his fingers off the door, pushing and shoving and brandishing his gun.

Harry stumbled back and the door slid shut, locking with a distinct little click.

"You are needed," said Sorenson, still in that strange, hollow-sounding voice that wasn't his. "The first."

If Sorenson wasn't Sorenson, then who was he? The alarm bell in Harry's head was becoming deafening.

"The first what?" he asked.

"The young must flourish," Sorenson continued as if he hadn't heard. He went over to the console nearest the quarantine bay and began to disconnect the equipment, pulling the main power cable free from its socket.

"What are you doing?" Utoblo squawked.

"Access is needed. Power is needed. You are needed." Glassy-eyed, speaking like a man in a trance, Sorenson turned back to the crates, and he'd been obsessed with his crystals before, but not like this. "There must be sustenance before we go forth. It's almost time. Almost time."

He bent over the glowing, pulsing crystals and became utterly absorbed in them once more.

It was definitely time to evacuate. Harry pulled Utoblo over to the beds, where de Haan was still sleeping peacefully, and hissed, "Is there another way out of here?"

"I don't know what to do." Utoblo's eyes were wide and scared, the brown of the iris barely visible, the pupils were so dilated. "Can't let you out, I can't let you out, Captain's orders. And he won't let me." He waved wildly at the locked door. "But we have to. I don't know what to do."

Harry knew how it felt to be out of your depth and sinking fast. He'd felt much the same way when he first met the Doctor – still did, in fact, rather a lot of the time on these travels, encountering situations no amount of training could have prepared him for. But he was also quite certain they didn't have a great deal of time to indulge in panic.

"Sub-ensign Utoblo," he said, and then tried to remember the lad's given name, feeling that the familiarity was called for. "Ola. Look, I'm not sure exactly what's going on here, but I believe we're in danger. In fact, the whole ship could be in danger. What do you suppose is more important: following orders from a captain who doesn't actually know what's happening, or finding a way to protect ourselves – and perhaps everyone else, as well? Is there another way out of this room?"

Utoblo stared at him, breathing hard. Then he blinked and rubbed his eyes, and was suddenly calm again.

"There's a storeroom. It connects to the astrometrics lab, shared space. But the connecting door'll be locked too. We'll be trapped in there."

"So long as we can bar the door at this end, it's better than nothing." Harry carefully unconnected de Haan from the monitors and plasma infusion unit, unwilling to leave her behind even to continue her treatment, because whatever was going on with Sorenson and those crystals was dangerous, he felt it with every fibre of his being, and she'd be quite defenceless in this condition. "Quickly, before he notices."

He carefully scooped de Haan up into his arms as Utoblo scurried across to the far wall, hard to make out in the shadowy murk of the darkened room.

Then, "I can't find the door!" Utoblo called out, too loud, and Sorenson let out a shout.

"What are you doing? You aren't to leave. Your bodies are needed for the young."

"Needed for what?" Utoblo squawked. "I can't find it – where's the door?"

"Turn on the lights, Ola," Harry shouted, hurrying across the room with de Haan in his arms and Sorenson hot on his heels.

There was a scramble. Not enough light to see what was happening – or to avoid obstacles – and Harry stumbled under de Haan's weight, felt Sorenson catching at his arm…

The light came on, Utoblo at the wall-mounted control unit. Rather unexpectedly, Sorenson let out a yell and collapsed.

Harry let himself breathe again, while Utoblo's eyes almost popped out of his head, staring from Sorenson to the control panel at his hand and back again.

"I didn't – I just – is he dead?" he asked.

Across the room in the quarantine bay, the crystals appeared to be almost _flashing_ now, emitting a strange sort of whining, crackling sound. Harry looked at Sorenson's crumpled form and knew he couldn't take the time to check if the man was still breathing – still less to ascertain if he were back to himself or halfway round the loop still, or whatever had been wrong with him.

"The door," he said. "Quickly."

Utoblo operated another control and a concealed hatch slid aside. They hurried through into the dark, cluttered room beyond, where Utoblo fumbled with another wall-mounted control panel to switch on the lights and seal the door behind them and suddenly everything was very still.

But the persistent crackle-whine of the crystals in the next room could still be heard, even through the dividing wall.

dwdwdwdw

"Oh, I could do with a really big glass of wine just about now." Sarah sat down alongside Samina Landa with a sigh.

The Doctor had plunged right back into the computer console, trying to complete work on that buffer he was building to protect the solar cell, and Vishinsky was at his side at least trying to look helpful – but Landa, unusually for her, had not gone over to help. Instead she'd taken herself off to a quiet corner and slumped to the floor looking miserable, so Sarah had followed, because even if she did want to be alone, they were supposed to stay in pairs for safety.

Landa didn't reply. Sarah tried to think what else to say.

"I'm sorry. Wijaya was a friend of yours."

"He was an idiot," Landa muttered. "A layabout, always slacking off, cracking jokes…"

"Shall I take that as a yes?"

"It wasn't supposed to be like this." There were tears in Landa's eyes. "He only stayed down here because I was, didn't want to lose face. He could have gone back to the probe."

"I'm not sure he'd have been any safer there." Sarah thought about her own idiot friend, who didn't even know what the danger was but was trapped up there with it nonetheless.

"I don't want to die," Landa whispered. "This mission…it wasn't supposed to be like this."

"You were charting, weren't you, before you were diverted for the rescue mission," Sarah recalled. Boring, Wijaya had called it, a far cry from all this, and Vishinsky had said the crew were inexperienced.

"And we weren't prepared – we weren't prepared for this at all." Landa squinted sideways at Sarah suddenly. "You seem to be, though. You've been one step ahead of us from the start, and we still don't even know who you really are."

Were they back to that again? Sarah sighed.

"We're travellers," she said. "That's all. The Doctor likes to travel, it's what he does. Harry and I came along for the ride, and when we heard the distress signal we stopped to investigate. That really is all there was to it. We just had a more open mind than your lot because we knew we weren't responsible!"

Landa frowned, unconvinced. "But no one just travels without a planned destination – you must have some kind of purpose, some mission?"

Sarah shook her head. "No purpose, no mission, just exploration."

"You don't have any official function at all?" Landa seemed to find this a difficult concept to grasp.

"Not on the TARDIS, no. When I'm at home I'm a journalist…or, I was." She faltered, remembering just how long it had been since she actually worked. She still investigated, all the time – that was half the fun of life with the Doctor – but the results these days were rarely publishable. When had she last filed copy, seen her name in print? The career that had once meant everything seemed to have fallen by the wayside somehow, almost without notice, yet she couldn't quite bring herself to care because, "I don't know any more, I don't know how long this journey will last, I just know it's worth it. To be out here, seeing the universe, exploring new worlds…but you must feel the same, surely. You work for some kind of space agency, don't you?"

"Space Corps," Landa instantly corrected. "Our work is mostly routine – charting and patrolling. We don't generally get to see many sights – and if exploring new worlds is like this, I'm not sure I'd want to!"

"Oh, but it isn't always like this," Sarah hastened to assure her, before honesty compelled her to add, "Well, actually I suppose it is often like this. But it's also wonderful – think about it, we've discovered a whole new life form here. No one ever knew it existed, and here we are."

"Great. We've discovered a new life form that wants to kill us," Landa sourly observed.

Sarah let out a shaky little laugh because there was that. "Well, you can't have everything."

dwdwdwdw

"My mum told me not to join the Space Corps," Utoblo unhappily muttered, slumped in a heap on the floor beside de Haan's comatose form. "There's no future in it, she said. Rustics from a dirt-ball moon like Torah never make it, she said. I told her I'd make captain."

"Perhaps you will," Harry distractedly replied, ear pressed to the storeroom door trying to make out what was going on back in the medical bay. That crackling sound was growing louder, he was sure – and he was almost certain he could hear movement. "So long as we survive this…is there another way out of here?"

"I told you, it's locked."

Harry picked his way through the clutter of stored equipment to check the other hatch anyway, just in case. It was locked.

"Told you," said Utoblo.

"Can't you open it? I really think we need to put more distance between us – it sounds as if Sorenson is waking up."

That brought Utoblo to his feet, quick smart, his narrow face blanching with alarm – but then he sat down again. "He's not the only one. Carly? Carly, are you awake? I think she's waking up!"

De Haan was stirring. Harry felt a rush of relief that his improvised treatment had actually done the trick, that the patient really was recovering – and not before in time, in the circumstances. He picked his way back across the room as de Haan groaned and moaned and clutched at her head.

"Ow," she murmured, sounding more than a little hoarse. "Oh, my head."

"It's all right." Harry knelt and took her wrist to check the pulse. Strong and steady, just as it should be. "Take your time."

She pulled her hand free to rub at her eyes, blinking at him bemusedly as she muzzily murmured, "You were locked up," and it wasn't even the most recent occasion she'd be thinking of, Harry knew.

"Ah," he said. "Yes, well, er…things have moved on somewhat since then."

"We're in trouble, Carly," Utoblo burst out. "There's something wrong with those crystals Professor Sorenson brought aboard, like they're about to explode or something, but the captain doesn't know and he won't listen and he left Commander Vishinsky behind, and now we're stuck in here!"

"What?" De Haan was understandably confused by this babble of information. She struggled to a sitting position and looked around to see where she was, brow furrowing. "Why are we…? Did you say explode?" Her voice sounded terribly weak still. "What's going to explode?"

"In there!" Utoblo pointed frantically at the connecting door leading back into the medical bay. "He's gone mad, the professor! And we're stuck – I don't have access to astrometrics!"

"I do." De Haan began to gingerly pull herself to her feet, looking distinctly wan and wobbly, readily accepting the helping hand Harry offered. "Did you say the commander was left? Left where?"

"On the planet," Harry told her. "My friends as well – and other members of your crew."

"But why –?" She stopped and shook her head. "No, tell me later. You said something was going to explode? We should –"

There was a sudden yell of fury from the medical bay. Sorenson was definitely up and about again – and had noticed their absence.

De Haan's eyes widened. "We should get out of here."

"My sentiments exactly." Harry helped her across the cluttered storeroom to the other door, Utoblo fluttering at her side. De Haan had a kind of key-card, a tiny plastic square, which she used to unlock the hatch, allowing them through into the room beyond, the lights in here coming on automatically as they entered.

Harry looked around to see where he was now – the astrometrics lab, Utoblo had called it. An enormous curved screen set into the far wall dominated the room, with a series of control panels beneath it and more workstations around the side walls. Another door presumably led out into the corridor and de Haan headed straight for it, all but towing him along as she hung onto his arm for support, weak still but determined.

She hesitated when they reached the door. "Wait, where are we going? Do we have a plan?"

"Er…well, not as such." Harry had thought no further ahead than escape from the immediate threat.

"Is the guard still there?" Utoblo asked in a hissed whisper, and de Haan boggled.

"There's a guard? Why in the skies were _you_ locked up?"

"I wasn't! He was!" Utoblo gestured indignantly at Harry, who couldn't deny it.

De Haan shook her head bemusedly and used her card to open the door, allowing them to peer very cautiously around it just in time to see the guard, further along the corridor, opening the medical bay door. He stepped inside with a grouchy "What's going on in here?" that was drowned out even as he spoke by a sort of prolonged popping noise that sounded almost like the muted rattle of a machine gun…followed by the distinct thud of a body hitting the ground.

Not the explosion Utoblo had feared – but perhaps something somehow even worse.

"What was that?"

"What just happened?"

Both de Haan and Utoblo were looking at Harry as if they expected him to have all the answers. The trouble was, of course, that he didn't.

He took a deep breath and tried to think. The guard had made no further sound and Sorenson had also gone quiet.

"I think we should find out what's happening – and see if that man's all right," he decided, medical instincts surging to the fore. "Wait here."

"No," de Haan promptly countered. "No, I think we should stick together."

So they went together, venturing slowly and cautiously along the corridor toward the medical bay, an odd glow now emanating from its wide open door. The temperature dropped noticeably as they grew close, a strange sort of thrum to the air that Harry had felt before – and he knew what it meant, with a creeping sense of dread that sat at the pit of the stomach like a stone as realisation dawned.

They reached the door. All lights and monitors now dead, the darkened room was instead faintly illuminated by an icy mist that filled the air above the overturned crates that had once held crystals, sparking and crackling in electric reds and blues about the power sockets. The wizened body of the guard was barely visible, shrouded by the mist, which wisped and flickered and crackled all about him in a manner somehow reminiscent of wasps swarming around a spot of jam.

Sorenson had talked about _young_ and about sustenance, about needing _power_ and _bodies_, and it all made a horrible sort of sense now.

Sorenson looked up, his expression one of rapt triumph. His mouth opened, the mist began wafting toward them…

And the door slammed shut. De Haan swiped her card to seal it with an urgent shout of, "Run!"

They ran.

dwdwdwdw

"That's it!" the Doctor excitedly shouted. "It's done!"

Sarah bounced to her feet and hurried over as he extricated himself from beneath the computer console looking tremendously pleased with himself.

"The buffer is complete?" Landa had followed her and bent to peer at the connections, as if reluctant to take his word for it.

"But will it work?" Vishinsky wanted to know.

The Doctor shrugged. "We'll find out soon enough. Night's candles are burned out and jocund day stands tiptoe on the misty mountain top. Or something like that." 

Neither Vishinsky nor Landa appeared any the wiser, but Sarah knew her Bard when she heard him. She followed the Doctor's line of vision toward the window and saw that the first rays of dawn were at last creeping over the treetops.

"It's getting light."

"That's what I said," said the Doctor, adding, apropos of nothing immediately apparent, "I met him once, you know." 

"Who?"

"Shakespeare," he said, as if it should be obvious. "Charming fellow. Dreadful actor."

"Perhaps that's why he took up writing," Sarah distractedly replied, attention focused on the rosy glow over the treetops, wondering how long it would take. How long until they knew whether or not the Doctor's buffer was successful, holding the Natara at bay from the electrical power they craved? How long until the solar cell recharged sufficiently to make contact with the space probe? How long until the Natara came up with a new approach, how long could they protect themselves, how long until the space probe itself came under attack from the Natara on board?

"Perhaps it was," the Doctor rather absently murmured, likewise watching the sunrise.

How long?

dwdwdwdw

"Captain!"

"Captain Salamar!"

Utoblo and de Haan both shouted wildly as they burst onto the bridge ahead of Harry, breathless from their mad dash through the halls of the space probe, spurred on by the alarm that now signalled ship-wide alert.

The captain's initial reaction was perhaps, in hindsight, only too predictable. He took one look at Harry and bellowed, "You! What have you done?"

Harry was dumbfounded. By the time he regained command of his voice, Utoblo was already babbling.

"Sir, the aliens – the aliens are on board, the aliens from the planet, they're here, in the medical bay, it was Sorenson, sir, he was helping them, and they're here! We have to do something!"

Salamar blinked and blanched and gaped and finally stuttered, "W-what?"

"It's true, sir." De Haan leaned heavily against the door frame, thick curly hair tumbling loose to hang lank around a too-pale face. She was far from fully recovered, Harry noted with professional concern, and really shouldn't be up and about yet – never mind dashing around like this.

"What do you mean?" Salamar asked in a very small voice. "What are you saying? Professor Sorenson…"

"I believe he's being controlled somehow," Harry offered, looking around for a chair of some kind for de Haan. He'd been thinking about this. It was the only explanation that made sense of the professor's behaviour, his change in attitude – the voice that wasn't his.

"By the aliens?" asked Salamar wonderingly, as if he could scarcely believe it. "The aliens are on board? Is it really true? But how can that be?"

"The Doctor did try to warn you, you know." Harry spotted an unused operator's chair at a workstation nearby and pulled it across for de Haan, who pulled a face but sat down anyway, rubbing at her shadow-ringed eyes. "They were in the crystals the professor brought aboard. We left them contained in the medical bay, but they'll be loose by now, I'm certain."

The alarm continued to sound in support of this supposition and the lights were flickering, just as they had when the aliens attacked down on the planet, but Salamar only stared, slack-jawed, while his bridge crew shuffled around in agitation, waiting for him to take charge and tell them what to do in the crisis.

The command wasn't going to come, that much was increasingly apparent, and they really couldn't wait any longer.

Harry thought of Brigadier Lethbridge-Stewart back at UNIT, utterly unflappable whatever the crisis. Commodore Bennetts at Faslane, Captain Arnold on the Ark Royal…not one of them would have left their crew hanging like this.

Someone had to get them moving again, and perhaps the decision to break rank was easier when it wasn't your own chain of command.

He turned to Morelli and employed his very best Brigadier impersonation to ask, "What's our status here?"

She blinked in surprise and glanced uneasily at her captain, but he no longer appeared to be listening, even – shock, Harry diagnosed once more; the man really required treatment, but they could hardly shuffle him off to the medical bay, in the circumstances.

Morelli looked helplessly at Utoblo and de Haan, and other members of the bridge crew, then back to the captain again, as if unable to decide what to do, unable to choose to go over the captain's head when he was standing right there…but the alarm was still sounding, there were ghostly invisible aliens loose on the ship, and at last she took a breath, turned her back on the captain and answered: "We're experiencing unexplained power losses in pockets all around the ship, equipment failure and blackouts. Two crewmen reported dead –"

"Make that three," de Haan interjected in leaden tones. "Matthiesen's in the medical bay – he was the first."

"Four," the crewman called Anwar spoke up, looking grim. "They just found Leisha Karim – no wait…" He raised a hand to the earpiece he was wearing, listening intently. "That doesn't make sense. They say Karim is dead. But they also say she's on her feet and moving…like a zombie."

"There's no such thing as zombies," Morelli immediately reproved.

"Tell that to Karim!" Anwar retorted. He frowned, hand rising to his earpiece once more to signal another incoming communication. "And Farrez – and Varley. I'm getting reports from all over. The dead won't stay dead!"

It sounded impossible…but Harry had seen 'impossible' proved otherwise before. He exchanged worried looks with de Haan, who shakily offered, "If the aliens could control the professor, perhaps they can do this, as well."

"Perhaps." Harry turned to Anwar. "Do your reports say anything about temperature? It always drops when the aliens are near."

"And lights!" added Utoblo excitedly. "They shut down the lights – but Sorenson collapsed when I turned them back on."

Morelli seized on this at once. "We can use that."

She cast a fleeting glance sideways at Salamar, who still hadn't moved, hadn't spoken, seemed lost in a world of his own. Poor chap really had cracked – but that was the least of their worries right now.

Giving up on her captain, Morelli turned back to Harry. "We need to mount a defence. What else do you know about these creatures?"

dwdwdwdw

One by one, the computer systems in the base were flickering back to life, the buffer to hold off the Natara was working, and the Doctor was almost unbearably smug about it.

"Yes, yes, you're brilliant and we all know it," Sarah cheerfully agreed with only a slight roll of her eyes, because the praise was deserved even if he was fishing for it. "But is the radio working yet?"

The Doctor grinned happily. "Let's find out."

They moved as a group to the radio and here Vishinsky and Landa took over, adjusting the controls to their satisfaction before attempting to transmit.

"Zeta Minor calling space probe KX9-06. Zeta Minor calling space probe KX9-06 – come in, please."

There was no response, only the faint crackle of static drowning out the other faint crackle that signalled the continued presence of the Natara, lurking on the threshold between dimensions – the daylight had beaten them back, at least for now, but they hadn't gone far.

The Doctor frowned. "May not have quite enough oomph yet – let's see if we can boost it, divert power from redundant systems…"

He pushed the others out of the way to fiddle with the controls himself, and leaned into the microphone.

"Hullo up there, space probe! This is Zeta Minor, are you receiving?"

There was a pause, another crackle of static – then at last actual words, garbled by bursts of white noise.

"…Minor, this is…06…you…there…"

"They've heard us!" Sarah exclaimed.

"More or less," Vishinsky dryly remarked. He made a move to reclaim the transmitter, but the Doctor was already talking again.

"Hello? You're breaking up – can you hear me?" He began fiddling with the controls again.

There was another burst of static, which cleared up as the Doctor played with the dials, and then a blessedly familiar voice rang out, clear as a bell.

"I say, Doctor? Is that you?"

Harry. Safe and well and not locked up after all. Sarah laughed out loud with relief, while the Doctor beamed from ear to ear.

"Harry Sullivan! It's good to hear from you. How are things up there?"

A slight but ominous pause followed before the reply came back, "Not too good, I'm afraid," and Vishinsky promptly wrenched the microphone from the Doctor's hand.

"What's happened? Where's the captain?"

"Commander Vishinsky?" A new voice, greeted by Vishinsky as Morelli, came over the airwaves now to deliver a terse and alarming report, confirming that the worst had transpired: the spores had germinated and the Natara were loose and wreaking havoc on the space probe.

"Turn the ship around," the Doctor immediately ordered, taking control of the microphone back from Vishinsky. "It is imperative that the Natara are returned to Zeta Minor – they won't make it easy for you, they've set their sights outward, but they must not be allowed to reach populated space or there'll be no containing them. Do you understand?"

Sarah could hear a desperate note in Morelli's voice as she replied, "Yes. But the pattern of progression indicates they're moving toward Main Engineering – they can seize control of the whole ship from there. How do we stop them? We thought light…"

"Light will hold them at bay, surprise light shocks them into letting go," said the Doctor, nodding to an audience that couldn't actually see him. "The brighter the better, but if they've begun to feed off your power supply, all bets are off. It strengthens them exponentially. Their grasp on this plane is tenuous and can be disrupted, but remember we're no longer dealing with one or two guerrilla raiders but a whole swarm. That too will lend them strength. Think, think." He rapped at the side of his head again, brow furrowing with thought. "Exploratory space probe – you have laser equipment aboard, perhaps a photonic field generator or five?"

"Of course." It was Vishinsky who replied.

The Doctor nodded thoughtfully. "Then there might be a way…"

dwdwdwdw

The Doctor really was a tonic. He needn't even be in the room – merely exchanging a few words with him from thousands, perhaps even millions of miles away was enough to instil new hope and raise the gloomiest of spirits. Harry didn't know how he did it, but was grateful nonetheless.

He was also at something of a loose end as that brief conversation with the Doctor came to an end with a rush of activity, Morelli visibly uneasy still with her assumption of command, yet taking charge of the crew quite capably, issuing orders and organising everyone, as per the Doctor's quite detailed and highly technical instructions. Harry wasn't part of this crew, had no official function here and very limited knowledge of the ship and its contents, so, without much he could usefully do to contribute at this stage, it was perhaps only natural that he was the first to notice what was missing.

"I say, where's Captain Salamar gone?"

Morelli was in the middle of a ship-wide communique, warning the crew to close all hatchways, stay in groups and keep handheld lights with them at all times. She faltered and glanced around sharply, but continued to issue instructions while the rest of the bridge crew looked around in consternation.

Captain Salamar was nowhere to be seen.

"He's run away," Utoblo accused with a scowl, looking thoroughly disillusioned with his captain, but de Haan was concerned.

"No, he was listening. How much did he hear? Would he have tried to go after the creatures alone?"

"We can't worry about that now," Morelli determinedly said, setting the radio aside, communique complete. "We'll keep an eye out for him, but we have to continue as planned." She turned to eye Harry appraisingly. "Are you sure you want to be part of this, Lieutenant? You're not on this crew, you could stay here…"

"I'm quite certain," said Harry, who had no intention of waiting tamely on the bridge while Morelli led a team against these Natara creatures; he'd had quite enough of that already, left to stew in the medical bay while this blasted ship took both him and the TARDIS ever further away from Sarah and the Doctor. "I may not be on your crew, but I'm no civilian. I've as much at stake as anyone."

"Well, I won't say no to the extra hands," said Morelli. "All right, then. Anwar, de Haan, the bridge is yours. Barricade the door and try not to die. The rest of you – lights on and let's go."


	8. Chapter 8

**Part Eight**

Away from the command centre, the corridors of the space probe were in semi-darkness now and Harry was thankful for the heavy-duty flashlight he'd been issued as he made his way through the ship in the midst of a party that included Morelli, Utoblo and two other crew members called Reig and Ranjit. The bland, featureless hallways were now broken up by solid steel barriers, sealing off the various sections of the ship and slowing their progress, as these hatchways had to be opened and closed manually to allow them through. Whether or not they might also slow the progress of the Natara creatures was less certain, but worth a try, it had been agreed.

The ship was strangely quiet now, its crew, Harry presumed, hunkered down at battle stations and assembly points – hopefully in groups with portable lights at hand, although neither, the Doctor had said, was a guarantee of safety, merely the best chance they had.

"Through here," said Morelli, breaking the silence as she led the way along a side corridor to a door that she unlocked using a key-card.

This was some kind of supply area, and the four Morestrans set to work at once gathering up the equipment they needed, handing their flashlights to Harry as they worked. Arms full, he fumbled and juggled awkwardly, and then almost dropped the lot when Morelli rocked back on her heels in dismay.

"There's one missing. I think de Haan was right – Captain Salamar has gone after the creatures alone."

dwdwdwdw

"This is rather a new sensation for me," said the Doctor.

Sarah's head jerked up with a start – she had, she realised, been on the point of nodding off, in spite of everything.

Shifting uncomfortably from her position on the floor, where she'd been resting against the computer console, she looked around, yawning. Vishinsky and Landa were just across the way, talking quietly as they shared a ration bar, while the Doctor paced about the room playing idly with his yoyo. There was a slight chill and crackle in the air still, but the broad daylight was holding the Natara at bay, for now – until such time as the space probe made it back to the planet there wasn't really much more they could do.

And that, of course, was what the Doctor was complaining about.

"What, you mean having to sit around waiting while someone else acts? Welcome to my world," said Sarah, who'd spent more time than she cared to remember waiting and worrying while the Doctor was off doing something dangerous or other that she couldn't be part of.

The Doctor pulled a face.

"I don't like it," he declared as if this were headline news, and continued to pace around the room looking disgruntled, before brightening. "Still, I suppose I can use the time to master my reverse trapeze."

It took a moment for Sarah to realise he was talking about the yoyo.

"Oh, only you could mess around doing tricks with a yoyo at a time like this!"

"Well, if you have any better suggestions."

"All right, here's one for free. You've told Harry and the others how to contain the Natara on the space probe, and if they succeed they'll head back here." She had to stop to take a breath, because it was such a horribly big _if_, and the other side of that _if_ was unbearable: _what if they didn't make it?_ But they would make it, they had to, and Sarah determinedly pressed on. "But what happens then? How do we get the creatures off the ship, had you thought about that? I mean, they're invisible, so how can we know for sure they're all gone?"

The Doctor stopped playing with the yoyo and looked at her, a twinkle in his eye and a funny little smile tugging at the corners of his lips. Sarah knew that look. She should have known.

"You have thought about it."

"Well, I do have one or two ideas," he said with a grin, practicing his yoyo trick again.

She smiled back, buoyed by his confidence – but still wanting to know more, to be certain, because she knew him too well. "Such as?"

The Doctor lost concentration and the yoyo swung around and hit him on the nose.

"Well, there's the snag, you see," he admitted as Sarah, amused, went over to help him untangle himself from the string.

And there it was. "Oh, I might have known there'd be a snag!"

"It _should_ be straightforward enough," he continued, winding the string back onto the yoyo as if nothing had happened. "We can flush the Natara out from the probe using the dimensional stabiliser matrix in the TARDIS, but the snag is, of course…"

"That the dimensional stabiliser matrix is in the TARDIS," Sarah finished for him, seeing the problem, because the TARDIS, of course, was on the stricken space probe.

"Exactly. So until it gets here…" The Doctor eyed his yoyo speculatively. "Perhaps I'll try walking the dog instead."

dwdwdwdw

"Why would he do it?" The question came from young Utoblo, who couldn't seem to get his errant captain off his mind. "Why go alone – he _heard_ – it isn't safe…"

"He may not care," Harry quietly said, remembering the look in Salamar's eye – the shock, the panic, the _failure_. The man had broken, left his crew to make shift for themselves, and there'd been no time to do anything about it. The greater emergency had to take precedence and he couldn't regret that, too much depended on resolving the crisis, but he did regret, very much, that he'd not been able to do anything for the captain. He'd become a doctor for a reason, after all.

But then again, he'd also joined both the Navy and later UNIT for a reason. Perhaps he should count his blessings that the two halves of his profession only rarely came into conflict.

"He's trying to save face," said Morelli, also very quietly. She looked troubled. "But I had to assume command – we couldn't wait for –"

The lights went out, all at once, and corridors that had been at least partially lit were abruptly plunged into total darkness.

Well, total darkness aside from the portable lights carried by Harry and the others, which seemed an extremely flimsy form of protection, all of a sudden, as the shadows pressed in around them.

"They've reached Engineering," was Morelli's verdict, a faint wobble to her voice. "It's the only place they could hit all the lights at once."

"Is it much further?" It wasn't until he'd spoken that Harry realised he was whispering, although quite why he couldn't say – the spookiness of the darkened corridors, perhaps; too easy to imagine an invisible alien lurking in every shadow.

"Not far – it's just along –" Morelli broke off as a shadowy figure lurched around the corner toward them. "Who's that? You shouldn't be in these hallways alone – go to…"

Her voice trailed off as the figure moved closer, pausing at the edge of their combined flashlight beams, head tilted quizzically, its features shrouded in shadow.

Utoblo narrowed his eyes, squinting. "Is that Chung?"

"Chung?" A note of desperate hope lifted Morelli's voice. "Chung, are you all right? What are you doing?"

Only natural, perhaps, that they'd hope, that they'd not want to believe the worst – it was their crewmate, their comrade – but Harry could see now, through the shadows, could make out the features, wizened and shrivelled. Dead. A zombie, like Anwar had said.

It was already too late. And he was almost certain they shouldn't get too close.

He remembered what the Doctor had said and stepped forward, raising his flashlight to point the beam right at the figure, and the effect was every bit as dramatic as when Utoblo turned the lights on back in the medical bay: the crewman, Chung, collapsing on the spot the moment the light beam hit him.

Harry shivered at the cold draught that seemed to speed past as the man fell – the Natara that had possessed him taking flight, perhaps, unless it was merely imagination. He was prepared to concede at this point that it might be.

His allies surged forward to cluster around the man's body in shock and revulsion at what had been done to him. They'd forgotten themselves, in the heat of the moment, lowering their lights – leaving themselves wide open. Feeling rather an intruder to this moment of grief, Harry made sure to hold his own light high, sweeping the beam around in hopes that this might hold the invisible aliens at bay.

There was no sign of further movement and the ship seemed deathly quiet, an icy bite to the air.

Safety in numbers, the Doctor had said, but the creatures would pick off any stragglers, so just how far did one have to stray from a group to be vulnerable? And how safe would even a large-ish group remain if the creatures were drawing power from the ship's systems? They'd used such stolen power to attack the whole ship earlier. Yesterday. Had it been as long ago as that? Between exhaustion, adrenaline and the now-defunct artificial illumination of the spaceship, time seemed to be blurring, impossible to keep track.

The hairs at the back of his neck were prickling. Was that a crackle he could hear, just at the edge of audibility, or was he imagining that, too?

"I think we should move on," he said.

Morelli straightened, looking as if she'd very much like to be sick.

"Yes," she said, composing herself. "Yes, keep moving. We won't let them take anyone else."

They peeled themselves away, left the dead man lying where he'd fallen, and moved on, but hadn't gone more than five paces when they heard yelling from up ahead.

"That's the captain," Utoblo shouted in alarm, and then the four Morestrans were running, all semblance of proceeding according to any sort of plan thrown out the window in an instant.

Harry pelted after them, wondering grimly what the Brigadier might have said about Morestran military discipline – or lack thereof. The air around him seemed to be alive all of a sudden: bitingly cold and crackling with menace. This was really not the moment to be separated from the group.

He'd had cause to be thankful for long legs before and was again now, catching up with the others as they burst into a wide, high room that could only be the engineering deck, full of machinery and control panels – and Natara. There were at least half a dozen crewmembers in the room, seemingly dead yet active at the controls, wizened and glassy-eyed zombies – Sorenson among them, the only one who appeared unharmed, if not exactly healthy, directing operations – while the air was alive with still more of the creatures, invisible but for the odd crackle-hiss of electric red-blue yet palpably present and thrumming with energy.

The newcomers arrived just in time to see Salamar's body crumple and fall, the cumbersome device in his hand hitting the floor alongside him with a clatter; he'd never managed to operate it. They were too late – for him, at any rate, but there were still other lives to save, including their own.

But now every eye in the room was upon them – even those that couldn't be seen, Harry was certain. There were five of them, in a group and with lights, but the creatures were swarming, drawing power from the systems – so who exactly had the advantage here?

"Morelli! Senior Crew-leader Morelli, come in!" de Haan's voice unexpectedly crackled over the communicator. "The ship's turning around again, resuming course for Morestran space – we're locked out of the helm. We've lost control!"

Morelli had that queasy look about her again, transfixed by her zombie shipmates. She thumbed the communicator, voice wavering very slightly. "All right, Ensign, stand by."

In that same moment of distraction, Harry saw Sorenson's impassive expression curl into a leer, arms raised like a conductor. Salamar's body was stirring, rising – just another zombie now. The air was like ice and that crackling sound became almost deafening, the air thick with red-blue sparks that were rushing toward them, seemingly heedless of the flashlights still in their hands.

"Now!" yelled Harry in panic. "Do it now!"

For a handful of agonising seconds the Morestrans fumbled with the unwieldy equipment they'd hauled from the storage locker, and the Natara were upon them now, freezing and choking…

Utoblo got his switched on first, flooding the room with an oddly-tinted light that was dazzlingly bright, the brightest light Harry had ever seen. There was an unearthly shriek that seemed to come from everywhere and nowhere and he could breathe again all of a sudden. Ranjit wasn't far behind, then Morelli and finally Reig got his lit as well, and the light was so bright now it was blinding.

Harry groped for the dark-tinted glasses he'd been issued and rammed them on, blinking furiously to clear his eyes of the colourful spots dancing before them as he looked around to see what had happened.

The Doctor had talked at length about what should be done and how to go about it. He'd talked about photonic field generators and laser light, about lux and lumens, linking this or that doodad and switching the thingumajig to project through the whatsit – it had all been so much double-Dutch to Harry. Seemed to have worked, though. The air was clear again – warm, even – there wasn't a crackle to be heard…and the room was littered with corpses.

"Get to work," Morelli ordered in a shaky voice.

That powerful burst of super-light would effectively disperse and repel even a large swarm of the creatures, the Doctor had said, but would quickly drain the batteries of the equipment, so there wasn't a moment to lose. While Morelli rushed to a control console to release the helm and get the ship turned back to Zeta Minor, the others set about linking their handheld equipment into the ship's central power supply, and here Harry was able to lend a hand at last. He may not understand this technology, but he could lay out cables and strip wires with the best of them.

They had four of the photonic field generator thingummies, and retrieved the one Salamar had taken to make five. Wired together and linked to a central power supply, they formed a very rough-and-ready protective barrier to keep the engineering deck flooded with light and the alien creatures out.

"They aren't really designed for this, I just hope the connections hold," said Morelli.

"What about the others?" Utoblo asked in a small voice. "The rest of the crew – those things are still out there…"

"There's nothing we can do," she replied, an agonised expression on her face. "We must hold the engineering deck – it's the only way we'll make it back to the planet."

"But what then?"

"The Doctor will have a plan," Harry stoutly assured them all – himself included. It helped to say it out loud. "First rate boffin, you'll see – got an answer to everything."

Morelli didn't seem entirely convinced. "I hope you're right."

So did Harry, but he thought it prudent not to admit as much out loud. With nothing more he could usefully do for the time being, he looked around with regret at the corpses littering the room – and realised with shock that one of them was moving.

"I say, Professor Sorenson!"

"He's alive!"

"It can't be…"

Amid disbelieving exclamations, Harry ventured closer to the man. Utoblo caught at his sleeve.

"Careful – it might still not be him. I mean…just be careful."

"Oh, I am, I assure you." Harry edged closer still, but not too close, and squatted, trying to get a look at the man. "Professor Sorenson? Professor, are you all right? Is that you?"

Sorenson raised his head. He looked absolutely ghastly – jaundiced and gaunt, with hollow cheeks and sunken eyes – but he was alive, definitely alive. Was he himself, though?

"Is it me?" he repeated, sounding both hoarse and indignant. "Who else would I be?"

"Well, it certainly sounds like him." Not sounding or behaving at all like himself had been the first sign of something wrong, so it followed, perhaps, that seeming himself again should imply that the possession had been broken – the light field driving the creature out and too intense to allow it to reclaim him as it had before.

It seemed logical enough, in theory, at least. In practice, Harry sat back on his haunches and watched the man warily as he struggled to his knees and looked around, squinting and shielding his eyes against the blinding brilliance of the light shield.

"I don't know who else I should sound like," Sorenson muttered crossly, but his expression changed as he began to notice the bodies scattered around the room. "What's that…no, no it can't be – what's happened?" And he turned on Harry in sudden, single-minded fury. "Where are my crystals?"

That settled it. It was definitely him.

dwdwdwdw

_Steak and kidney pie with creamy mashed potato and lashings of gravy…served by the Brigadier…who was most improbably wearing a frilly little waitress apron…that was odd…_

There was a loud burst of static and Sarah started awake with a gasp. It took a moment for the dream to clear, and by the time she'd realised with relief that Brigadier Lethbridge-Stewart was neither present nor dressed as a waitress, and with disappointment that the pie wasn't anywhere in the offing either, the Doctor was already deep in conversation with someone, somewhere nearby.

Vishinsky and Landa had also been asleep, she groggily realised when she saw them helping one another up – and she remembered now, the Doctor had offered to keep watch and let them rest a while. So who was he talking to? Was that the radio she'd heard, the voice was familiar…?

"That's de Haan!" Landa exclaimed, rushing over to join the Doctor – as excited as Sarah had seen her yet.

It was de Haan's voice, of course! And if she was talking on the radio, then that meant she'd recovered, that Harry had managed to save her life. As much as she'd liked the other woman, who'd been so friendly and kind, Sarah was surprised to realise just how relieved she felt. It was the first bit of properly good news since they'd landed on this wretched planet – she hadn't known quite how much she needed it.

She pushed to her feet, every limb feeling like lead. However long she'd slept, it hadn't been nearly long enough.

"When this is over, I'm going to sleep for a week," she muttered as she joined the others at the radio. "So what's happening now?"

"The probe is on its final approach," the Doctor announced, ceding control of the radio to Vishinsky, who began to anxiously enquire after his crew.

"Approach?" Now Sarah knew she wasn't properly awake yet, because that took a moment to sink in, as well. "So they've done it? They're nearly here?"

The Doctor's smile lit up his entire face. "They've done it. They're nearly here."

"Oh, thank goodness."

"But it's not over yet," the Doctor immediately warned.

"Of course it isn't," she agreed, rolling her eyes.

Vishinsky set the radio receiver aside. He looked grim. "Morelli's team has secured Engineering and has control of the ship, but Captain Salamar is dead and the Natara are running rampant – total number of casualties unknown."

"We'll have our work cut out for us reaching the TARDIS then," the Doctor cheerfully observed, grinning as if the prospect filled him with delight. "Won't we?"

dwdwdwdw

"I don't understand," seemed to be the only thing Sorenson could say, when all was explained and done. "I don't understand, I don't understand," as if, like Salamar, something had broken somewhere inside.

The man was also badly dehydrated and in need of medical care, which Harry was once again unable to provide, confined as they were to the engineering deck. All he could do was make the professor comfortable, keep an eye on him, and try not to let his frustration show.

"I don't understand either," Utoblo muttered. "Why's he still alive? Why didn't those things kill him? They killed everyone else…" He looked across at his dead crewmates, their bodies now moved from the undignified positions they'd fallen in and neatly arranged at the side of the room.

"I really don't know. I suppose they must have wanted him alive – well, he was their first host, their spy. Perhaps they still needed him for something," Harry theorised. The Doctor would have a better explanation, he was sure, if only he were here. Soon enough, they'd be able to ask.

But not soon enough. Harry had always thought of himself as a reasonably patient sort of chap, but just now he felt thoroughly _im_patient, tired of waiting and wondering. They were so close now and he wanted, rather badly, to talk to the Doctor and Sarah himself – to find out what needed to be done next, what they were going to do next…to satisfy himself that they really were all right. But communications from engineering were internal only – planetary communication could only take place on the bridge, which meant that any news must be relayed second-hand.

At least the bridge had held, and de Haan was providing regular updates. The ship was about to land. Nearly there now.

"It doesn't seem right." Utoblo stood gazing at his dead crewmates. "Vaughan came through the Academy with me…and Alvarez, she was…and the captain! It's so…well." He crouched alongside the captain's body, regarded him sadly. "He wasn't a very good captain, I suppose."

It seemed churlish to say it now the man was dead, but Harry had to agree. It didn't mean he'd deserved what happened to him, though.

"Perhaps you can learn from his experience," he suggested. "See that you do better when it's your turn."

Utoblo's troubled expression broke and he beamed all over his face at the thought of the captaincy he aspired toward.

"Oh, I will," he said. "I will."

The ship jolted, very slightly, and they both looked around. Morelli was at the radio again.

"We've landed," she announced. "They're opening the main doors now – Commander Vishinsky's heading for the bridge."

"Is the Doctor still with him?" Harry promptly asked.

He both was and wasn't, was the reply. The Doctor and Sarah, it seemed, were heading for the medical bay – to do something with the TARDIS, although quite what de Haan couldn't say.

It was no good. Harry should, by rights, be exhausted, he knew, and the adrenaline that had brought him this far would present a hefty bill when all was done, but just now he couldn't have kept still if his life depended on it. He simply couldn't wait around a moment longer.

"Right, then." He snatched up a flashlight and headed for the door, removing his dark glasses – he wouldn't need them out there. "I'm going to find the Doctor."

"Wait, you can't go alone – those things are still out there." That was Utoblo, scurrying after him looking determined – although not so determined that he didn't shoot a quick, nervous sideways glance at Morelli for permission. "I'm coming too."

dwdwdwdw

The Doctor, of course, had never set foot inside the space probe before, and turned beseeching eyes upon Sarah as Vishinsky and Landa dashed on ahead of them, intent on reuniting with their colleagues and assessing their losses.

"Well?"

"This way."

Flashlight firmly in hand, Sarah led the way through dimly-lit corridors toward the medical bay, where she'd last seen the TARDIS. Signs of the Nataran incursion could be found everywhere, from patches of ice-cold air dispelled by her flashlight beam to damaged light fittings and torn electrical cables. They ran into only one animated corpse along the way, though: a woman who'd until very recently been young and full of life, with long dark hair and a set of colourful rubber bands around her wrist, a tiny quirk to offset the smart, severe lines of her uniform.

_What was her name? Who would she not be going home to?_ Sarah wondered as the woman's body crumpled and fell beneath her and the Doctor's combined flashlight beams. It felt almost like murder and she had to remind herself it was release. So many had been lost to these creatures, and the weight of them was heavy on her heart.

But there wasn't time for more than cursory passing respects for the dead – too many other lives to save, including their own, and the ship was not yet secure. They pressed on, and found the medical bay open but barred to them, the freezing air alive with electric red-blue sparks, crackling with menace.

The Doctor was fascinated. "They seem to have an idea what we're about – someone's been eavesdropping."

And even combined, two flashlights barely even put a dent in them, although they did at least hold the creatures at bay.

Sarah and the Doctor retreated to a safe distance to consider the problem, peering back around the corner for assurance that the creatures weren't following. They weren't, but they also weren't budging. Stalemate.

"Why can we see them?" Sarah caught herself whispering and made herself stop. Pointless. "Or sort of see them, anyway. We couldn't before."

"They've been feeding," said the Doctor, head tilted to regard the swarm thoughtfully. "It strengthens them, stabilises the manifestation – but we must find a way through. Perhaps if –"

"Doctor – Sarah!"

Sarah turned just in time to see a flying figure sprinting toward her at top speed.

"Harry!"

He was running too fast to stop gracefully and nearly sent them both headlong. Sarah gave him a hug and the Doctor grinned.

"There you are, Harry, it's about time you showed up. We need to get in there. Any ideas?"

Rather unexpectedly, Harry looked pleased with himself. "I might have, as a matter of fact – except…" His face fell again. "We may not have clearance to get through."

"Actually…we do." Ola Utoblo was with Harry, alert and agitated. He held up a tiny plastic card. "I took this from the captain's…well, you know. I shouldn't've – the commander'll…but I thought…well, just in case."

"How very perspicacious of you," the Doctor remarked. "But don't say any more." He nodded toward the crackling swarm, which was holding its distance but not far enough. "The walls may have ears. Show us."

"We'll have to move fast, then – they'll see where we're going, may already have it blocked off," Harry said in a low voice.

So they moved fast, heading for another door along the corridor that Utoblo opened using that purloined key-card. Wherever it led, it had been disregarded by the Natara – but for how long? Glancing over her shoulder, Sarah could already see them stirring, noticing – moving.

They ran through the door and across the room beyond to an odd little hatchway – it was a cupboard, a dead end, surely…but Utoblo and Harry confidently pushed inside and through the clutter of equipment within to reach the far wall, where there was another door.

This one came out in the medical bay – but the Natara were already swarming in, realising what they were about…and there were more behind them, cutting off their retreat.

"Run!" yelled the Doctor.

They ran, pelting across the room to the TARDIS. It wasn't far, no more than a hundred yards, yet it felt so much further, impossibly far. Sarah strained and struggled, invisible fingers catching at her, cold as ice, the air freezing around her, burning her lungs – it was like running against a force ten gale, frozen, icy, choking…it was too far, too far, they weren't going to make it…but then the Doctor was there, fumbling with the lock, and then they were all tumbling inside, and the door swung shut behind them.

Sarah leaned forward, hands on thighs, trying to catch her breath, while Harry redundantly remarked, "I say, that was a close one," and Utoblo stared around at the TARDIS interior in open-mouthed wonder.

A nasty thought occurred.

"None of the creatures made it inside, did they?" Sarah asked. If a Natara takeover of an ordinary spaceship was bad, how much worse would it be if they seized the TARDIS?

But the Doctor seemed entirely unconcerned. "No, I don't think so. They'll be sorry soon enough if they have!"

He gave her a cheery wink, already busy at the console, nimble hands moving swiftly and assuredly across the controls.

"So what now?" Harry asked.

The Doctor grinned. "Now, Harry, I'm going to end this."

He became engrossed in his work once more, disappearing beneath the console to pull out all kinds of cables and circuits.

Sarah bent to see what he was doing. "Anything we can do to help?"

The Doctor's tousled head reappeared.

"Yes," he said. "You can help a great deal by standing over there and keeping out of my way."

He disappeared beneath the console again.

Sarah looked at Harry, who said, "Well. That tells us, doesn't it?"

And then Utoblo found his tongue. "Um. What is this place?"

They attempted to explain, which was easier said than done – especially the clumsy way Harry did it, which Sarah then had to unpick – and at length it transpired that there was plenty they could do to help after all, the Doctor making use of all three of them to hold circuit boards and cables, which he looped around them as he worked. He was building something, and at last declared it complete.

"Bit of a lash-up, really," he declared, regarding the jumble of wires and equipment with smug satisfaction. "But it'll do the trick."

He turned the machine on.

dwdwdwdw

Harry hadn't a clue how the Doctor's contraption worked, but all that really mattered was that it did.

The Doctor kept blathering on about dimensions and frequencies – the man clearly thought he was explaining, but it was all so much double-Dutch, really.

The gist of it appeared to be that the device could detect the Natara creatures and sort of hoover them up into a kind of holding chamber that was no bigger than one of the Doctor's infernal bags of jelly babies yet could reputedly contain an infinite number of the formless creatures – _dimensionally transcendental, you see_, said the Doctor, beaming with pride – before spitting them back out again later, outside the ship and back into their home dimension.

It took several sweeps of the ship before the monitor atop the device stopped displaying the little pinpricks of brilliance that indicated the location of any creatures still hidden aboard. Quite what the Natara themselves thought of it all was unclear, since they had no means of communication, but with the bulk of the swarm captured within seconds of the TARDIS door being opened – well, they'd been waiting just outside, after all – they seemed to have accepted defeat at last.

The Morestrans, meanwhile, were venturing out of hiding and counting their dead – more than a third of the crew, but the Doctor seemed to think they'd got off lightly. Harry wasn't sure they'd agree.

"You must leave no trace," the Doctor told them. "Not a trace – nothing they can make use of."

Commander Vishinsky looked to have aged about 10 years since arriving on Zeta Minor.

"You're talking about the survey team's base," he said. "The solar cell – the equipment."

"It must be destroyed," the Doctor insisted, so they used the last precious minutes of daylight to venture out of the ship and across to the base, to set charges and blow the whole shebang sky high.

The Doctor, Harry felt, secretly enjoyed a big bang every bit as much as the Brigadier, however much he claimed not to. It was certainly an impressive blast.

"Well, that's that, then," said Harry when all the fireworks appeared to be over, but Sarah didn't seem convinced.

"They're still out there, though – watching us, resenting us, just waiting for an opening." She shivered reflexively.

Harry put an arm around her shoulders. "We'd better make jolly sure not to give them one, then."

"In the beginning," she said, "They were just defending themselves – protecting their world, their young. How many times have we done the same?"

"They killed an awful lot of people, Sarah."

"I know," she said. "And we've not actually destroyed a single one of them. We kept our promise, in the end. We've brought them all back and the invaders are leaving. It feels strange – to be among the invaders."

They were approaching dangerously philosophical ground now, so it came as a relief to Harry that the Doctor reappeared at that moment, having carried out one last sweep of the ship in case of stragglers.

"Hallo, you two," he greeted them with a beaming smile. "Ready for the off?"

Sarah cheered up at once. "It's all done?"

The Doctor nodded. "I do hereby solemnly declare the space probe KX9-06 pest free! Vishinsky seems to think they've just enough power to break orbit and signal for emergency refuelling from the nearest way-station, so –" He broke off as the ship shuddered very slightly. "Compression units, I believe. She's taking off. Come on, it's high time we were going."

He strode off in the direction of the medical bay and the TARDIS without any further ado.

"Just a minute, Doctor," Sarah protested, hurrying after him. "We haven't even said goodbye to anyone."

"Oh, fiddle-faddle," he blithely dismissed. "Vishinsky's people are short-staffed – they'll all be far too busy to bother about us. Come along."

They entered the medical bay, and there found that they weren't going to get away quite as farewell-free as the Doctor intended, because the room was occupied: Landa repairing damaged equipment, while Utoblo tended to Professor Sorenson, who was recovering.

"Apparently, I did such a good job assisting you, I'm stuck with this duty until we get back," Utoblo told Harry, equal parts rueful and proud. "But I'm not taking up the medicking full-time – I still mean to be a captain someday."

"Oh, I've no doubt you will, old chap, no doubt at all," Harry said with a grin, shaking his hand.

The Doctor, meanwhile, was talking to Sorenson, who remembered very little of what had happened and was fretting about the loss of his crystals.

"My researches – I'd discovered a new source of energy…"

"No, no, no, Professor," said the Doctor, very gently. "I think you'd abandoned that line. You'd decided to concentrate on deriving energy from the kinetic force of planetary movement."

Sorenson stared at him. "Had I?"

"Oh yes," the Doctor solemnly replied. "Large source of untapped energy there."

"The kinetic force of planetary movement," Sorenson murmured. "What a brilliant idea!" 

And Sarah was talking to Landa, who regarded the TARDIS bemusedly.

"It's a box – how can you travel anywhere in that?"

Utoblo laughed. "It's bigger than it looks!"

"But where are you going?" Landa asked. "You don't really just…travel, with no destination and no mission – no purpose?"

"Of course we've a destination," the Doctor briskly told her. "Come along, Sarah, Harry. We've an appointment in London and we're already thirty thousand years late."

Harry grinned, waved to the Morestrans and followed him into the TARDIS.

"By the way, Harry," the Doctor remarked as he operated a lever to close the door behind them. "I never did say: thank you for bringing the TARDIS back."

"My pleasure, Doctor – I did have something of a vested interest in the matter."

"Oh yes." The Doctor looked shifty. "Our appointment in London, you mean."

"Well, I did promise the Brigadier. I'm supposed to be seeing you safely back."

"And a splendid job you're doing too," the Doctor evasively replied, busying himself about the controls and avoiding eye contact.

Harry knew him more than well enough by now to recognise that manner – and what it meant. _Here we go again_.

Yet as he caught Sarah's eye, he realised that he didn't mind the thought of another detour nearly as much as he'd have expected – and certainly not so much as he no doubt should. _Make sure he gets back to London in one piece_, the Brigadier had said, and the job wasn't done yet. They'd get there in the end.

"Doctor," said Sarah with faux-sternness, amusement dancing in her eyes. "You said you'd take us back to London five minutes before we left."

"Oh, I did, I did," the Doctor cheerfully agreed. "But of course, arriving in London five minutes ago doesn't mean we have to go straight there…"

~end~

© J.B., April 2015

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